# Silly newbie tricks



## gadget_lover

I propose a thread for those of use that are NOT machinists to share our screw-ups and successes so others can learn from them.

I'll kick it off with some lathe items that might be obvious to old timers.

Did you know that if you open the jaws of tstock 7x10 3 inch chuck, you can gouge the heck out of your cross-slide by moving it too far to the left? Not only will it take a chunk out of the cross slide, the chuck will keep turning!

When you change the gears for different threads, it makes a BIG difference if you put the B gear where the C gear belongs. In the case of a 40 tooth and 45 tooth, the difference was not enough to notice. The flashlight did notice.

Did you notice that the change gears are mounted on an arm that swivels? I didn't. It really cramps your style when you can only use 10 combinations of the gears.

The 16 or so threads listed on the harbor freight housing are not even a fraction of the threads you can cut. If you use one of the online programs to figure your cear combinations, make sure it includes all the gears you have. Some of the programs don't base their calculations on the same gears that you got with your lathe. 

Does this thread have any appeal to others?


Daniel


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## jtice

lol damn gadget, learning the hard way are we? /ubbthreads/images/graemlins/grin.gif

Yea, I ALMOST had my chuck hit the cross-slide.
Scared me to death lol

Good thread though, there are alot of little things like this, that ppl just wont know, unless you tell them,,, or they learn the hard way. /ubbthreads/images/graemlins/wink.gif


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## gadget_lover

Another trick... and why not to do it.


I have a 3 jaw self centering chuck. I threw a piece of 3/4 inch delrin into the chuck. The jaws were the set that grab the outside of a rod. It was not quite centered, but I was just playing, so it was not critical.

I faced it, getting a good 90 degree cut. Then I turned the piece down to 1/2 inch. Cool! Even though the piece was not centered, it was concentric when I was finished cutting it. I cut some threads to match a part that was sitting around.

So far so good.

Now here's why you should center the piece.

I took it out of the chuck and test fit it in the part. It was almost what I wanted. I put the rod back in the chuck and found it was almost impossible to get back into position. I had to keep rotating the piece in the chuck until the same imperfections lined up again. Even so, I could not get it close enough to it's previous position to be able to clean up the threads I had cut before.

I've since bought a cheap dial indicator and magnetic stand from ENCO (about $20) and use that to make sure it's straight every time.

If you don't have a dial indicator, you can use the toolpost as a visual guide. Just get teh work parallel with the edge of the toolpost and make sure it stays that way when the chuck is rotated.

Well, Other than the knurling wheel mixup, that' all I have so far.

Daniel


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## PEU

maybe you need this tool






(image from premium content of www.mini-lathe.com)

I purchased both standard sizes (55 and 60 degrees)

a dial indicator is in my wish list, also in the list a 4jaw INDEPENDENT chuck, because with my lathe came one 4jaw but self centering, which I found pretty useless.

Pablo


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## PEU

what I really need to figure out is a method of keeping all the tools in order in my bench, I keep looking for the allens, the brushes, the live center, all the cutting tools, keeping away the aluminium chips, is a real KILOMBO (mess) /ubbthreads/images/graemlins/smile.gif

Pablo


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## gadget_lover

I found that gauge in the ENCO catalog. I'm not sur about all the uses, but I did see a reference to using it to ensure you have the correct angle when cutting threads.

Another silly newbie trick:

When you are trying to turn several sections to the same depth, you crank in the topslide, make a pass over one section, then back the tool out to pass over the
section you don't want to cut... then repeat. The trick is to move the tool out and then back in the same amount each time by using the index marks next to the crank. I was doing things like stoppping at 27, then backing it out, moving over and remembering to stop at 27 the next time too.

This is made a lot easier if you zero the index after geting the first cut to the right depth. The index is a friction fit, so you can rotate it by hand while holding the crank steady.

Daniel


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## McGizmo

Peu,

I have a wood shelf above my Atlas lathe and since I use Aloris QC tool holders, I cut a long strip of wood matching the dovetail that mates to the toolholder. I mounted short sections of this on the underside of the shelf and can "hang" my tool holders there in plain sight and within quick reach. I now spend most of my time at another lathe where there is no such shelf so I have reverted to a dedicated drawer in a rolling tool chest for the tool holders. I would think that those magnetic tool holder strips wold be useful above a lathe and want to get one when I remember to! I see it as a temporary spot for holding the tools in use at the time; drill bits, end mills, QC holders and the like.

Staying abreast of entropy in a shop is never ending. /ubbthreads/images/graemlins/frown.gif I lost the battle some time ago........


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## PEU

[ QUOTE ]
*McGizmo said:*
Peu,

Staying abreast of entropy in a shop is never ending. /ubbthreads/images/graemlins/frown.gif I lost the battle some time ago........ 

[/ QUOTE ]
Magnetic holders RIIIIGHT, I have one of these in my kitchen for the knifes. Great Tip /ubbthreads/images/graemlins/bowdown.gif

There is always a scientific explanation for shop disorder:

The shop is part of the universe, so according to the big-bang theory (or the 2nd law of thermodynamics) entropy will increase with time, where entropy equals the amount of disorder in a system. With increasing disorder, there is inherently less energy that can be used to do useful work... /ubbthreads/images/graemlins/smile.gif

Pablo


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## tvodrd

I thought entropy was why a can full of beer seems to prefer being on its side /ubbthreads/images/graemlins/grin.gif . Wood blocks make great holders for round shank tools. They are easy to make/customize- just drill blind holes.

Larry


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## PEU

I finished my lathe mods

front view of the camlock tailstock





view of the camlock handle (made of a long 1/4" screw and a piece of aluminium)





Modification of the handles, so they are like the ones in the carriage and back of the tailstock. I changed these because the original ones kept unscrewing all the time.





and a BAD picture (due to backlight) of the lathe you can see in this picture that I machined a handle for the QCTP also, which uses the original screw as the core.





Now that I'm confortable with the lathe comes the hard part: make my 1st light /ubbthreads/images/graemlins/smile.gif /ubbthreads/images/graemlins/help.gif /ubbthreads/images/graemlins/smile.gif

Pablo


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## dat2zip

When first starting out, consider the type of work you are going to do and on your first order of raw materials (Delrin, aluminum etc) get enough diamater stock that you are going to be using. 

Do not do what I did and get 0.5", 1" and 1.5" assuming I'd be able to use one of them to turn down for the work I was going to do.

You should try to get stock as close as possible to the diameter you really need. Why? I found out that taking 1/2" off the diameter (Turning) takes literally a good hour and cranking the lathe back and forth. You can reallistically on Aluminum take 0.010" - 0.020" off per pass. That means a 1/10 inch takes 5 - 10 passes. The resultant swills of chips can easily overflow your lathe too.

While this is great exercise for the arms, it is very time consuming.

I've heard that using tubing is extruded and not necessary round as pure round stock. Be careful there.

When boring, try to drill out as much material (in steps) before using a boring tool. I found out again the hard way. I would drill a pilot hole big enough for the boring tool and started boring away. Well, if you have never used a lathe before, you can at best take 10 thous to 20 thous off per pass. A 1/10 inch takes a good 5-10 passes. 2/10 takes twice as many.

A good drill set is manditory. Don't get the cheap sets. They don't drill straight and thus your drilled hole usually ends up larger than you expected. This will ruin your work if this is your final drill size before boring and you only have 10-20 thous as a finishing operation. you might end up drilling a larger diameter past what you wanted very easily with a non straight cheap drill.

Chucking up your work. on the 3 jaw chuck. I tighten the chuck up till it almost grips the work. I then rotate and slide the part in and out. This movement helps the part from getting stuck and cocked in some strange angle. I keep moving the part (sliding back and forth slightly) while slowly tightening the chuck. This usually gets most items centered very nicely. Even short items where the chuck grips very little of the work surface. When all else fails I use a dial indicator mounted to a magnetic base to center the work surface.

For the mini-lathe, I find that I chop off just enough material to make what. Working with small diameters and soft parts past a few inches gets rather iffy real fast. Don't fool yourself into chopping off enough work material to make 2,3 or four off the same part. The added length will usually end up biting you, unless your stock is small enough to fit through the center of the chuck.

Items that are longer than 5-6 inches can apply a lot of lateral force on the part when turning. The longer the part, the lighter the cuts one might want to consider.

Parts do get hot when making a lot of cuts. Check you work if you been doing a lot of cutting on it. If it gets real hot hit it with some freeze mist or use a compressed air can upside down. Common day freeze mist and compressed air are the same. One has a tube down to the bottom and the other doesn't. Turning either one upside down reverses the roll of the can. A freeze can upside down is just compressed air and a compressed air can upside down is freeze spray.

With that in mind. You don't need to buy separate freeze sprays and compressed air. I buy a 6 or 10 pack of compressed air and leave a can near the lathe, workbench and computer.

I still have 10 finger!!! YAY.


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## MoonRise

Note: long stock through the chuck and headstock is not safe either. /ubbthreads/images/graemlins/frown.gif Especially long THIN stock.

It will rapidly transform from a long thin rod or tube into a long L-shaped bar whipping a large swath out the end of the headstock and the area around it. Not good.


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## gadget_lover

Thanks for the heads-up about thin stock poking out of the back of the headstock. I worried about bending it by accident, impaling myself on it and other things, but never occured to me that if it becomes imballanced at high speed it becomes a metal weed whacker!

That was a great contribution Wayne. Thanks for sharing. 

I should point out that the commmercial freeze sprays are not identical to the compressed air in all ways. I use the compressed air cans like Wayne does, inverting them to quickly chill hot parts. Use caution when using it on electronics. The commercial freeze sprays are avialble in 'zero residue' varieties while there are no assurances in the compressed air cans.

Now for the stupid newbie trick portion of this message:

Metal that's being ground gets hot. I knew that. What I forgot is that metal being sanded on a belt sander can get very hot too. /ubbthreads/images/graemlins/frown.gif I was trimming down the back of an aluminium Dorcy Spyder reflector in preparation for doing a luxeon mod. A wooden jig held the reflector at a nice 90 degree angle. 

After sanding a little I'd hit it with freeze spray and test it for proper focus. When the reflector was popped out of the jig I thought nothing of it. I reached out a snatched it off the ground and... promptly sent it flying as I snatched my hand back. I figure the temperature was just under the point where it would char wood.

So the lesson should be: grinding or sanding use gloves and glasses.

The other lesson, let parts fall an think before you grab them.

Daniel


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## PEU

a steady rest, a follower rest and a live center help with long pieces also

be sure to finish the piece without these, because they EAT a little of the rod in compensation for the work /ubbthreads/images/graemlins/smile.gif

Pablo


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## dat2zip

Here's another one that may be obvious to you machinist, but, is not intuitive to a newbie.

I've had my lathe now for what?? 6 mo's. I've gone through a lot of aluminum and delrin. 

I am just finishing an intro Manchining class for work and I watched in astonishment as the instructor proceeded to take off 0.2" while turning soft steel. My turning, facing and boring that I've been doing have not taken more than 0.020" off at a time. The binocular camera adaptor I did the other day I had to bore out the inside to 1.3". The whole job took a good 3 hours of cranking. It would have been duck soup if I bored off 0.05 or 0.1" in a pass. That one tip alone will save me countless hours of "exercise" on my forearms.

Now I'm fickled... Should I continue to exercise more or be more lazy?

Wayne


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## Eric_M

What kind of lathe are you using Wayne?

Eric


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## gadget_lover

Hey Wayne. Did the instuctor have to do anything different to take off that much, or was it just the use of sooft steel?

Daniel


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## wasabe64

Even though I have a QCTP, I still use the turret tool post occasionally. Since the retaining bolt that came with the QCTP is longer than the stock bolt (which is double-ended and harder to change), I machined a 3/4" long bushing out of 1" round aluminum stock to use the bolt that came with the QCTP. I can now quickly change between the toolposts for various operations - until I can afford more tool holders for the QCTP.

Interesting side note when it came to threading, the gear chart on my lathe was missing a 'B' column. So the gear combo for 20TPI was listed as 40t and 50t gears only. I'm glad I spent a lot of time @Mini-lathe.com while I was waiting for my lathe, or else I could still be trying to figure out how to make gears 'A' and 'D' make contact. /ubbthreads/images/graemlins/icon15.gif


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## PEU

Yesterday a friend of mine taught me a simpler way to thread:

instead of putting the cross slide at 60 degrees and using the dial indicator to see where you engage the leadscrew:

put the cutting tool square to the piece using the arrow tool shown in a previous post, move a few milimeters to the right of the piece, start the lathe with the leadscrew engaged, make the first light pass, without stopping pull away the cutting tool and then stop, then switch the lathe to reverse and start it again, move it all the way to the beggining and do the same increasing the depth of the cut a little.

You must not use the carriage handwheel, just back and fort using the forward & reverse, and the leadscrew must be engaged always.

Did I explained right?

Pablo


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## jtice

Wayne, I also take off VERY little with each pass.
Was the instructors lathe a small one like ours? Ive seen large lathes take alot off at once, but not small ones.

I bet if I try that, ill be snapping tools right and left. /ubbthreads/images/graemlins/icon15.gif


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## KC2IXE

Another trick - if you have a long thin rod out the headstock, build yourself a mount to hold your steady rest at spindle heigh, and use it to hold the stock from whipping


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## dat2zip

Eric,

In class there were Lablonde (sp?) lathes and one like Don has. Most of the mills were Bridgeports. At home I have a Harbour Freight 6X10 mini lathe and a micro-mark mini-mill.

(both use 3MT collets and englishized dials).

Heavy passes can be done with the following in place. The stock must be held in securely. The instructor was using a collet and had the stock 3/4 of the way into the collet. Thus, a very secured stock. On the 3 jaw chuck of the mini-lathe is about 1/2 the depth of the bigger lathes and thus would not grab as much stock. The motor must be strong enough to take the applied forces, stock must not bend, tool must be sharp, cutting angle and reliefs are proper etc... 

O, did I mention the stock must be held securely?

I just chucked up some scrap delrin and had no problem swiping off 1 revolution = 0.040 per pass of the cross slide. It's sweet. Stock 1.5" diameter. Speed was 300-400 RPM or pretty low. It took a lot of force to get the cut started and if I didn't apply a lot of pressure it would chatter. Once I maintained a constant pressure it cut real nice.

On the bigger lathes, one dial rotation on the cross slide is 0.2". On the mini-lathe it's 0.040. So, I would scale down according the size vs capability by the same amount. 

Aluminum is much easier than soft steel so it should cut very nicely. Practice on some scrap to see what your setup, diameter, tooling etc you are using can do. HSS tooling cuts easier than carbide. Carbide bits last longer.

The other thing to remember is how fast to turn your stock, drill or mill bit.

For the Speed and feed caclulations it's in the machinist handbook. That's what he said. I don't have one so I'll have to take his word on it.

I have a handout here that I'll enter some of it here and see if I can explain it.


<font class="small">Code:</font><hr /><pre>
Material Drill/Lathe SFPM Milling speed
Brass, soft bronze 200 160
Aluminum 300 240
</pre><hr /> 

There are a lot more materials and numbers but you can look those up if you need to use different material.

Here's the formula 
<font class="small">Code:</font><hr /><pre>

lathe or dill RPM 4 * CS
RPM = --------
D

Mill RPM 4 * CS
RPM = --------
D

Where:
D is the work or drill diamter (lathe / drill)
D is the cutter diameter (Mill)
CS is the SFPM from the table above.
</pre><hr />


Example. Turning 1/2" aluminum. RPM needed is:

(4 * 300) / 0.5 = 1200 / 0.5 = 2400

Of course the burning question I had the other day was:

OK, 2400. Great, *BUT* as you take material off, the diameter shrinks. Don't you need to change the speed. Especially when parting since it goes all the way to the center in some cases?

The answer is, yes.

Remember, Aluminum is very forgiving. You can cut at much higher speeds and get away with it. CNC machines automatically adjust the speed to maintain the proper cutting speed.  You can probably get away with much slower speeds too. I've always used more or less one speed on the lathe for almost everything I do and in general have not had any issues.


From the handout:

"NOTE:

Chatter: If chatter exists, feed should be increased and/or speeds reduced. machine setting: If machine cannot be set at the caclulated RPM, and the closest setting is more than 10% higher, use the next lowest speed setting."

Happy lathing all! (and milling too)

Disclaimer: I'm only repeating the instructor or handout. I make no claim of authority on subject matter presented here.


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## gadget_lover

Thanks Wayne. I see I'm cutting at speeds that are 10 times too low /ubbthreads/images/graemlins/smile.gif


Daniel


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## gadget_lover

I just finished a project. I made a 2 inch long body for my VIP. It's threaded on both ends (inside) and has a center section that's thinner than the rest. I'm quite happy with the result.

So where's the newbie trick? I started out all wrong.

I'd made the 45 minute trip to the metal market on Saturday and bout 25 pounds of aluminium bar and tube. I thought that I had everything I might need to make a new body for my VIP. I cut a 3 inch section of 1 inch stock (tube) and started to go to town. I faced the ends and had the outside nicely shaped before noticing that the inner diameter of the tube I had chosen was too big.

I should have grabbed the 1 inch bar and drilled / bored it out. I did not have the confidence to do that, and it would take sooooo long so I grabbed a piece of 1.5 inch tube that had an inner diameter that would be a touch big for the battery but fine for the threads.

The experienced guys are laughing by now. I started to turn the tube down to .998 inches. I figured I'd go a little long so I'd have some wiggle room.

Did you know that you get about 1 cubic foot of what looks like steel wool from turning 1/2 inch from a 1.5 inch bar? I had to clean my chip tray several times before I was finished. By the time I was done, I'd learned several things.

1) You can take big bites when using the live center and a good amount of speed.

2) You will hear the term hot chips from the veterns. Cut about 20 thousandths at 1200 rpm and the cutting oil will smoke! When the curls hit your hand you'll feel the heat.

3) I've done most everything before using around 200 RPM (see post above) and taking small bites (5 thou or so). I've mainly used the topslide adjuster to move the tool left to right while cutting. I found out that I can cover a longer area faster on the rough cuts using the handwheel in front.

4) Always start with stock as close to the right size as possible. You can spend hours making steel wool.

5) Clean off the bar before trying to center it in the chuck. Little bits of tape on the metal can make your dial indicator read funny.

I did learn from this, and got a great deal of practice doing rough cuts cleanly, so I guess the project was a success.

Daniel


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## McGizmo

/ubbthreads/images/graemlins/grin.gif

I made a shaving soap bowl with lid out of 2.5" solid Ti bar stock. I think I had a day's worth of Ti wool! Had it caught on fire! /ubbthreads/images/graemlins/icon15.gif


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## PEU

talk about hot chips when you turn at high speed a piece of steel, it's like getting bee stings in your hand...

I readed somewhere: if the chips ain't blue you're turning too slow...

I learned another thing yesterday, while doing a small piece for a fellow cpf member (MrAL) I tought that the piece was finished, and wanting to know if it fits ok in the back of the minimag, without thinking for a moment, I screwed it...

ERROR, when I tried to unscrew, it got stuck, it turned out that the threads where about 1/10 or 1/20 of a milimeter higher than the required size... resulting in about 10 minutes of aplying WD40 and cutting oil to try to unscrew the part, which finally came out.

I made a few wore cuts in the thread and voila! fitted like a glove.

Learning: Think twice, do once. Which goes right along with: measure twice, cut once...

Pablo


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## gadget_lover

"Think twice, do once. I like that. /ubbthreads/images/graemlins/smile.gif

Stupid trick of the day. My nicely turned VIP body was nice and shiny except for one little spot. I grabbed the dremel and mini whire wheel. UGH! Ugly! 

So I used rouge to buff out the blemish. Ran the buffing pad too fast and discolored the aluminum. UGH! UGH!

So I put it back in the lathe and turned off the barest smidgen (less than 1 thou) till it was perfect. Then opened the chuck and found I had jaw marks! UGH! UGH! UGH!

I finally took a 1 inch long piece of delrin and turned it down to where it just fit into the end of the body. I used that as a dead center of sorts (in the chuck) and used a live center (in the tailstock) on the other end. A quick finishing cut of about 1 thou made it pretty again.

Sheesh! Think twice, do once!

Daniel


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## gadget_lover

Today's learning.... When I use a parting tool (I use the 1/16 inch bar) it tends to leave a nice smooth finish on one side and a nub on the other. It seems inevitable that the nub will be on the workpiece that I've just finished, not on the other side. This is a shame seeing that the tooling swirls look pretty good by themselves.

I now have a left hand and right hand parting tool. I put just a few degrees of slant on the cutting edge (with a stone) so that one side cuts just a thousandth or so deeper than the other. When I part the piece I can predict which side the nub will be on.

Let me know if that was not clear and I'll elaborate.

Daniel


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## PEU

This is not exactly a trick, but working comfortably is part of the job.

I'm tall (1.87mts / 6.15 foot) and the lathe was on a office working table, so after about an hour at the lathe my back always is in pain.

So I made a working bench out of pine wood and an old Ikea tabletop







Its 1 meter tall (1.03 with the top), 1.50m long and 0.70m wide. I will put the lathe in front and the grinder behind it on the side, a small vise at the front right and voila! no more back pain /ubbthreads/images/graemlins/smile.gif

Total cost: wood $15, cuts were free, assorted screws/washers/nuts $10, top if I decide not to keep the Ikea one $20 (not sure yet).

Pablo


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## gadget_lover

That's a good looking work bench. The experts recommend a base as solid and heavy as possible to minimize vibrations.

I use my lathe on a "workmate" portable work bench. I like yours much better!


Daniel


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## PEU

I'm doing some bodies for 6 spare ARC AAA heads I purchased months ago. 

After trying many ways to do the negative contact for the end of the tube I came to this simple solution: 






used a low cost carbon steel drill, grinded to look like a milling cutting tool

It worked like a charm, is very inexpensive and for and added bonus is long !!

Yeah, not my best knurled part... /ubbthreads/images/graemlins/smile.gif

Pablo


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## gadget_lover

That's a great idea, Pablo.



Cutting inside threads requires that your single point tool be at the right height. The right height is exactly level with the center of the piece. This can be difficult to determine when looking inside something. I usually check the height of my tool by running it up against the outside of the piece with thin metal ruler trapped between the work and the tip of the tool. A business card or other thin cardboard works too. When the ruler is vertical I know the tip is at the right height. If the top leans away from you it's too high.

This trick does not work for inside threads.... unless you move the tool post
so the tool is up against the far side of the piece. Then you can do the ruler trick and get it right on.

Daniel


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## gadget_lover

Parting tools


Parting tools were a mystery to me. I tried all sorts of different tools and grinds. I read in some other threads that some folks use different methods for parting on their lathe. Some use a hacksaw, some use a dremel, some use a parting tool and some use a normal cutting bit. I've used all four methods.

The parting tool is frequently the best choice IF you set it up right. But first, which parting tool am I talking about? I'm talking about the 1/2 inch tall by 4 and 1/2 inch long by 1/16 inch wide blade sold by various places (including Harbor Freight). If you have a quick change tool post you probably got a holder to hold these vertically. If you are still using the multi tool (turret style) tool post that came with your HF mini-lathe, you have to get creative.

Here's what the parting tools look like. One is mounted in a quick change holder, the other is ground for use with the original Harbor Freight tool post.





OK, here's the tricks.
1) The tip of the tool has to be exactly on the centerline of the lathe. See the post just above for one way to center the tool's tip. If properly centered and with the proper rake you should be able to create long ribbons of metal.
2) You gotta have some rake on the top of the tool. Without rake you are scraping away at the piece you are parting. With rake you are shaving off the surface. I read somewhere that 11 degrees was about right. 10 seconds on the grinder was enough to make a nice rake in the top edge. I have also used a diamond coated wheel in my Dremel to cut the rake while it was in place.
3) Make sure the tool is at a 90 degree angle to the piece that you are parting. It should go straight into the piece you are parting. If there is any angle it will bind and either stall the lathe or break.

Here's the tool, the holder and the tool in use. Note the nice curl (blue arrow) coming off the tip. You should be able to make ribbons that are several inches long.






If you are using the HF turret, you have to grind down the tool to almost 1/2 of the height. You also have to come up with a way to hold it in place. Here's my HF setup. Notice the pair of 1/4 inch bits on the inside and the shim on top. The shims are made from the metal straps that held the shipping crate together. The shim keeps the screws from pushing it out of allignment as they are tightened. The heavy aluminum bar on the outside was to make sure the parting tool stayed vertical. I got lazy and did not cut it down.










The blue circle shows where the turret's set screws cut into the soft shim. I fine tuned the height of the tip of this tool by using my dremel while the parting tool was mounted on the lathe.

A quick word about rake: I saw several people using parting tools with no rake on the top or sides. When I got my new tool post I ground my tool to follow their example. That was a mistake. The tool chattered and cut little chips instead of curls. It dug in several times, stalling the lathe. I ground the rake and it works beautifully.

Do not be suprised if parting off a small part creates a big pile of shavings. They are so thin that they puff up like steel wool.

A sharp parting tool is also good for making grooves and fins in lights.

Daniel


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## gadget_lover

Collets and off center work.


I set up a home made threaded holder on a 4 independent jaw chuck today so I could do some minor milling in some ARC twistie tail caps. I'd used this before to accurately drill some other ARC tailcaps. The holder is a simple 1 inch long delrin rod (1.25 inch) that has been bored and threaded for an ARC tailcap.

I got it set up perfect. The dial indicator did not even move as I turned the chuck. Coool!!! I chucked up a short thin drill bit in the tailstock and drilled a perfect hole in the center.

Then I got in trouble.

I re-adjusted the jaws to offset the cap so that I could drill a second hole 1/4 inch over from the first. That worked as expected. Yehaw! I did it right. I chucked the next size drill bit and hit it again. This time the drill bit wobbled! I checked everything, and it was still tight. I tried a different drill bit. Thunk, thunk, thunk. Still not right.

So I decided I'd that the tailstock somehow had too much play. So I mounted a boring bit on the tool post and turned it on. I started to make a nice circle. Good problem solved. No... Wait.... Thunk, thunk, thunk. An interesting two lobe circle appeared on the end of the tailcap.

Here's what happened. When using a threaded holder, the work piece might tighten itself by an extra fraction of a turn. If this happens when it's centered in the chuck, it makes no difference as it's still centered. If it happens when you have it offset, the place you were drilling, boring, milling etc moves away from the center of rotation. You end up with strange patterns and uneven cutting sounds.

Speaking of thunks. I learned how to bore ovals too. Using independent jaws, tighten all 4 jaws, then back off the ones at the side 1/4 turn. The piece wobbles as you try to bore it, and you end up with an oval. It's not repeatable and not really a true oval. I mention it as a caution.

Daniel


----------



## PEU

For parting almost always I use a saw, at low speed and patience it works just fine, there is no need for cutting fluid. 

And when the parting tool is the only option, I grinded a similar parting tool in an almost identical way as yours, but I don't get that long strips of aluminum.

Pablo


----------



## gadget_lover

Thanks. I forgot to mention low speed; somewhere south of 400rpm for a 3/4 inch rod.

I get short strips and chips if the tip is not centered, or if I don't have enough rake. What's worked consistantly for me is;

1) grind the rake by holding the tool flat on the rest at a 90 degree angle to the edge of the coarse wheel. Grind only a little at a time to keep it cool.

2) A quick clean up of the cutting edge by holding it vertically and barely touching the end against the fine wheel.

3) A quick swipe of sides and bottom with a sharpening stone to make sure there are no burrs.

That's all.

Daniel


----------



## CNC Dan

Good work gadget.

The angle on the top of your tool is positive rake. There are tools that have no rake, or negitive rake. For negitive rake you need more power and rigidty.

It looks like you are feeding too slow, the chip should be thicker. But then again this is a smaller machine than I have ever seen.

Comercial cutoff tools that I use at work have a grove along the top that makes the chip fold down the middle, making it narrower than the groove that is being cut.

Dan


----------



## gadget_lover

I jut got a micro mill from Harbor Freight, so I can make a whole bunch more silly mistakes^H^H^H^H^H^H^H^H^H tricks.

The micro mill can actually hold a work piece that's the size of quite a few paperbacks stacked on top of each other. This is enough for my needs at the moment.

Ok, silly newbie trick:

I wanted to make a new tool holder for my lathe's QCTP (Quick change tool post) so I cut a 2 inch piece of 1.75 x 1.5 inch square aluminuum stock with a portable band saw. The cut end was pretty rough from the teeth of the saw and minor saw movements.

I decided to face it in my new mill. I clamped the stock vertically in the vice that's attached to the mill table. I chucked up a 3/8 end mill and made several passes acoss the top till it was nice and smooth. You could see the swirls from the teeth on the end of the mill, but it was nice and smoothe and flat. I turned it over (the stock, not the mill /ubbthreads/images/graemlins/smile.gif ) and did the same to that side.

After I finished making a tool holder for my cutofff tool (and it does work, thank you) I came across the army course 9-524 "Fundamentals of Machine Tools".
This tutorial talks about horizontal milling machines. That's when I realized that the SIDES of the end mill are designed to be used to create long flat surfaces. Horizontal milling machines appear to frequently use the mill in a horizontal position and the work is on a table underneath the mill.


So I took a fresh piece of square stock and trued the end using the side of the end-mill. It came out very smooth and perfectly flat. Amazed is a good word for it.

My second discovery came when I set that block on a know flat surface to check how true I'd managed to get the end. The end was very true, but 3 of the sides I'd thought were flat actually had a slight bulge (about .005). It ppears to have been part of an extrusion process somewhere. The 4th side was shinier than the others and it was perfectly flat.

I can post pictures if anyone needs it. [edit] Aw, what the heck. The left one was machined using the end of the end mill. The middle one was machined using the side of the end mill. The right one is raw from cutting with a hack saw.






Notice the middle one is smooth enough to see my thumb print?


Daniel


----------



## PEU

congrats on your new machine, machine envy from Argentina /ubbthreads/images/graemlins/smile.gif !!!


I have a question, I received my last purchase from LMS (a tool set and an indicator with base) 

I need some advice on how to use the indicator properly. 

I mean, where do you put it, how is used, etc etc. I did some quick tests late yesterday, but I cannot grasp the gist of it.

And for the piece measured, how do you adjust the missalignments.

Thanks


Pablo


----------



## gadget_lover

Hi Pablo,

I know of two types of indicators, dial indicators test indicators. The difference is that the dial type has a spring loaded plunger that has up to an inch or so of travel. As the plunger is depressed, the needle spins. The Dial indicators are frequently found with each division on the face equal to 1/1000 of an inch movement (accurate to .001)

Test indicators have a little lever at the end that move left/right. The one I have has only bout .03 inch swing. It's accurate to .0005

Using the dial indicator;

These are used mainly in setup of your work, though you can use them after to check that the cut was consistant.

To test that your work piece is centered in the lathe chuck, you'd attach the magnetic base to the headstock or the ways, and set the end of the plunger on a smooth part of the work piece close to where you will be cutting. Rotate the chuck by hand and watch the needle. It will rotate clockwise at high spots, counterclockwise at low spots. To adjust your work in a self centering 3 jaw chuck, you can try rotating the work in the chuck (hoping for a better fit) or gently tapping the high spot with a plastic hammer (moving or bending the piece) till it's close enough. With an independent jaw chuck you adjust each jaw till it's perfect.

The test indicator seems to be the best bet when you want to center the BORE of a piece. The bore is not always concentric with the outside surface. I had a heck of a time with one piece (trying to thread the inside of the hole) till I realized the bore was off-center by many thousandths. A test indicator only moves a little, so you have to have your work close to centered before you use it.

With the mill, I've so far used it to ensure that the work is mounted so that it moves in a straight line when I move the table, and that the top is level. This ensures that the mill will make nice straight and parallel cuts.

They make several devices to help you measure cleanly. Look into surface plates for a perfectly flat surface, or a comperator stand. Both provide a reference point to measure while moving the piece around.

Indicators are frequently used to cause paranoia, as in "I got my new lathe but the chuck was .002 off!" or as a point of pride as in "MY chuck is ONLY .002 off!" /ubbthreads/images/graemlins/smile.gif

When using any of the above, it's important to clean off the piece being measured. I was checking something last night and the needle jumped back and forth. It was picking up the grit on the surface that I thought it was just a stain.

Did I even come close to your question????

Daniel


----------



## PEU

will try, will tell Daniel, Thanks


----------



## gadget_lover

I have a heck of a time doing precision measurements when boring holes in things. I bought a mill to make that a little easier. Then I realized that the mill's fine feed (vertical) dial is 2/1000 per mark. This is after I ruined a piece by taking off 80/1000 where I meant to take off 40/1000. The proper solution is a DRO (Digital Read Out) that tells you exactly how far the head of the mill has moved. DROs are not cheap. The cheapest I've seen are at littlemachineshop.com for under $50 and the most expensive was on ENCO's site for over $4000.

Enter the poor man's DRO. This one is attached to the mill. The quill (the part the chuck is attached to) moves about 1.5 inches. The whole head moves up and down with the quill. I leveraged that fact to attach a $10 dial indicator (from Enco's sale ending today) to the part that holds the quill. The plunger of the indicator is depressed by the movement of the head.

I first did this with two sided foam tape. On piece on the front and one on the side. This allowed the lug of the dial indicator to help support the weight. I put masking tape over the lug, so that it would be held securely against the foam tape. It was very tight and worked well.

Here's the pictures....
In the first one, the dial indicator can be seen attached to the right hand section of the quill support. It has a black face. In the second, you can see how they have cleverly marked the fine tune knob for .002 per division and the one on the right marked (on the feed handle) .005 per division. Here's the fun part: The fine tune knob has 10 divisions before the first number, which is 10, but means 20. *sigh* The dial indicator is marked in .001 and reads just the way it should.













Off subject just a touch. I used the mill to make the bracket that holds the indicator. I cut a T-slot in it using a Dremel tool bit (#199 - 9.5 mm High Speed Cutter) in the mill. It's like a slotting saw. First I cut a groove using an end mill, then used the dremel tool bit. It took 3 passes to make it deep enough for the head of the bolt. I can move the indicator up or down as needed just by losening the bolt.


Daniel


----------



## jtice

I still have a HELL of a time parting /ubbthreads/images/graemlins/frown.gif

I have read through all the tips and tricks, but still cant seem to get it to work well.
I have ground many bits, trying to get the right shape, etc. Nothing seems to work.
I get alot of chatter, and the bit doesnt want to cut well, an dit I force the bit into the part hard enough to start it cutting again, it ussualy catches, and breaks the bit. /ubbthreads/images/graemlins/frown.gif

I have tried lube, but that makes it worse, it stops chattering for the most part, but then is wont cut at all.

-John


----------



## PEU

try with a saw, if you can finish the part later, I found no better way.


Pablo


----------



## jtice

Peu,

Thats what I always have to end up doing, using a hacksaw, which cuts just fine, BUT

Like last night, I was parting off a threaded tube, to make Arc LS retainer rings,
Well, they kinda needed faced after that, but its really had to chuck them back in the lathe, seeing how they are small, and you are holding onto the threads, which is not good. /ubbthreads/images/graemlins/frown.gif


----------



## gadget_lover

If it's catching when you try to cut, it may not be centered correctly. I found two critical angles. The side of the bit HAS to be 90 degrees to the work. The cutting surface is the very end, and it should be parallel to the work.

Have you tried raising or lowering the bit just a touch? Someone wrote that if you have it too high, it will bite into the work and jam. I use the ruler squeezed vertically between the end of the tool and workpiece trick. The shape should be similar to what I posted above.


Let us know if position was the only problem.

Daniel


----------



## wasabe64

If I need to grip a threaded zone to finish, I'll usually machine out a slotted sleeve of aluminium or brass to grip the piece in the chuck (kind of like a collet). It helps to protect the threads, but grip is still compromised - so take very light cuts.

I don't have any chatter with parting off work, but I've cooked my controller twice when the piece I was parting grabbed the parting blade. 

[ QUOTE ]
*jtice said:*
I still have a HELL of a time parting /ubbthreads/images/graemlins/frown.gif...

...I force the bit into the part hard enough to start it cutting again, it ussualy catches, and breaks the bit. /ubbthreads/images/graemlins/frown.gif

I have tried lube, but that makes it worse, it stops chattering for the most part, but then is wont cut at all.

-John 

[/ QUOTE ]

I have noticed that as well. I use a parting blade rather than grinding one out of a tool bit. When the cutting stalls, I jog the compound slide over a little to the left or right and it starts biting into the metal again. Ideally, I'd like to know how to stop that kind of behaviour.


----------



## gadget_lover

Got Plug taps? Well, sort of.


I found a need for a plug tap. but did not have any.

I drilled a hole in the cast iron support of my mill, then tapped it for 6-32. I did not want to drill too deep because I was not 100% sure what was on the other side of the face I was drilling. So I drilled 1/3 inch deep for a screw that was almost that long. I tapped it with a standard taper tap. I only got good threads on the first 3/16 of an inch.

I had 3 different taps that were 6-32, but all were tapered. I figured I could sacrifice one of the taps, so I got my Dremel tool and it's 1 inch diamond coated cut off wheel. The diamond wheel cut through the tap like butter. In seconds, the last 1/8 inch was gone and I had a passable plug tap. I ran it into the hole and had threads almost all the way to the end!

It's not at all scientific, but it did the job. Now I have to start a new container for altered taps. /ubbthreads/images/graemlins/frown.gif

Daniel


----------



## PhotonFanatic

Try getting the top-of-the-line tools:
http://www.carboloy.com/products/elecatalog/TURNING.pdf

See pages 284-286.

I believe you will find the shape of their inserts will make a big difference, not to mention the hardness of the carbide inserts.


----------



## PEU

an image is worth a 1000 words:







Pablo


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## PEU

I finally figured out how to use the dial indicator (thanks daniel) and I love it /ubbthreads/images/graemlins/smile.gif

I figured out that is not necessary to align to 0, you can do all the measurements relative to the actual position of the indicator, this way, I can move the carriage back, put the indicator over the ways, measure the piece, remove and continue working, this is practical and fast!!!

Now I can rechuck a piece and align it properly, niiiice /ubbthreads/images/graemlins/smile.gif


Pablo


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## gadget_lover

The use of the dial indicator makes a world of difference. The ability to see exactly how far off a piece is makes the difference between a precision fit and a sloppy one.

It seems that everything falls into one of two camps... Either it's something you work by eye and make up the dimesnions as you go or it's something where you measure everything repeatedly till it's jusssst right.

I need a surface plate to help with layouts and marking things precisely.

OH, Harbor Freight has their cheap dial indicators on sale for under $7.

Daniel


----------



## gadget_lover

Silly newbie trick of the night:

I was turning a small piece on my 7x10 lathe. I needed to cut a cam on a piece of 3/4 inch rod, so I used the 3 inch chuck with 4 independant jaws. I'd used it before to good effect. I had learned how to accurately center a piece of stock by adjusting each pair of jaws. No sweat.

So I first center the 5 inch long rod stock and turn down the last inch to .625 inches. Then I need to make the last 1/4 inch .44 inches in diameter, with one edge the same as the edge of the .625 section.

I'd played with this enough to know that I want the centre of rotation .22 inches from the edge, and that meant I had to offset the work piece by .11 inches.

I started adjusting the two jaws that would shift the work over. It just did not seem to want to work right. I finally got it offset and started to turn. I'd made only a few cuts when I realized the work was loose in the jaws.

Here's the learning for the night. The hole in the center of the chuck is just over .75 inches. I'd stuck the .75 inch rod into that hole as normal to keep the area I was turning close to the chuck. That meant that the rod was being forced against the inside of the chuck as I tried to offset it. One of the jaws was not even touching the rod.

I extended the rod out to where it was only supported by the chuck and repeated the process. The turned areeas came out just right, with both areas sharing a common edge and the diameters right where they should be. The result was perfect. Well, it was perfect except that I parted the dang thing about .018 too short. But that's another story. I'll repeat the process again tomorrow.

Daniel


----------



## PEU

you share, I share, we share /ubbthreads/images/graemlins/smile.gif

I'm using the dial indicator like is there no tomorrow /ubbthreads/images/graemlins/smile.gif, one trick I learned when I work with a piece that needs to be rechucked, is to make a little mark with a pen to align that part of the piece with the same part of the chuck.

This way when you rechuck, you reallign these marks and adjusting is much easier. 

The same technique is used at tire shops /ubbthreads/images/graemlins/smile.gif

Pablo


----------



## gadget_lover

Good tip Pablo. Thanks. I guess I should get in the habit of marking it when I first put the work in the chuck. I never remember to mark it just before removing it from the chuck.


I have a correction for last night's post.

*Calculating offset for turning lobes.*

Sometimes you need to turn a section of a rod that's offset from the center of the rod that's in your chuck. In the picture below I needed a battery contact centered in the main disk, then a post on the opposite side of the disk that was offset.







To do the offset post I needed to move the rod over to the side so the center of rotation was offset from the center of the rod. I wanted the side of the post to be about 10/1000 in from the edge of the central disk.

I first few prototypes worked fine, so I did not realize that I was calculating the offset incorrectly.

Here's the right way to do it.

Given: A rod .750 inch in diameter.
Given: A lobe .440 inch in diameter.
Given: You want the lobe and the rod to share a side.

Start by centering the rod. Don't tighten the jaws.

You need to find the center of the rod (.375) and the center of the lobe (.220). The center of the lobe will be located .220 from the edge. That means you subtract the radius of the lobe from the radius of the rod, .375 - .220 = .155

If you use a 3 jaw chuck, you'd need to insert a .115 shim between the rod and the third jaw. On a 4 jaw chuck you loosen the back jaw and tighten the front until the offset is exactly .155 inches. I push the work back and measure against the toolpost with a caliper. Then you tighten the top and bottom jaws to take up the slack caused by moving the center of the rod away from them.

You can verify that you have the right center of rotation by setting up your tailstock with any center. It will point at the center of rotation.

I had originally used 1/2 of the radius when I did my prototypes and just happened to chose a rod diameter where that happened to work properly /ubbthreads/images/graemlins/frown.gif I got all screwed up when I changed to a slightly smaller rod and found I was running off the edge of the disk.



Daniel


----------



## PEU

NEVER NEVER NEVER 

do any work that needs a little presure on a thin walled piece (facing, knurl, etc): 






I wanted to do a finish pass on an already finished piece, and this is the result...

This was the body of the wooden flashlight I'm building, already threaded, tested and working /ubbthreads/images/graemlins/banghead.gif /ubbthreads/images/graemlins/banghead.gif /ubbthreads/images/graemlins/banghead.gif /ubbthreads/images/graemlins/banghead.gif /ubbthreads/images/graemlins/banghead.gif /ubbthreads/images/graemlins/banghead.gif

Pablo


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## gadget_lover

ooooo. /ubbthreads/images/graemlins/blush.gifuch: That hurts!

I've one like that. So does Unnerv. I've seen his. /ubbthreads/images/graemlins/smile.gif

I've taken to making arbors or collets for those instances where I have to work on a piece that's almost finished. I hate having to duplicate a finished piece.


In general, I wonder what works best when deciding the order in which to machine things like this?

in your piece you have;
stock reduction
threading
knurling
finish pass
boring
drilling


Daniel


----------



## Heath

[ QUOTE ]
*dat2zip said:*
Parts do get hot when making a lot of cuts. Check you work if you been doing a lot of cutting on it. If it gets real hot hit it with some freeze mist or use a compressed air can upside down. Common day freeze mist and compressed air are the same. One has a tube down to the bottom and the other doesn't. Turning either one upside down reverses the roll of the can. A freeze can upside down is just compressed air and a compressed air can upside down is freeze spray.

With that in mind. You don't need to buy separate freeze sprays and compressed air. I buy a 6 or 10 pack of compressed air and leave a can near the lathe, workbench and computer.


[/ QUOTE ]

I was reading back through this thread and just saw this. My jaw dropped. This is a bad, bad idea for a couple of reasons. In the machine shops that I've worked in, compressed air of any sort is expressly forbidden as it turns metal chips into flying razors. I've had to visit a doctor to cut bits of metal from my eyeball, it is not pleasant. Also, if the metal gets stuck above the retina, it can permanently damage one's vision. I believe using freeze mist is probably a bad idea because it will very likely quench steel parts making them lose their anneal and difficult to machine. I also imagine that it can't be good for HSS tools. It's probably best just to use cooling fluid and keep the speeds and feeds down to manageable levels.

Note that carbide tools actually cut better with a certain amount of heat.


----------



## wasabe64

On the topic of cooling, I tend to cut dry for AL or steel if I'm using carbide cutters (brazed or indexable). The heat does not seem to be as much of an issue if I keep the cuts light. Proper chip formation and removal will also help keep the heat down.

The only time I use cutting fluid is when I am drilling or reaming, and this is more to protect the tool than the workpiece.

If you are cutting with fluid/coolant, be sure to maintain the flow of fluid/coolant at all times during the cut. This will help the tool maintain a consistent temperature. Intermittently 'quenching' a hot tool will shorten it's life.


----------



## gadget_lover

The wrong way to mill.

I was playing with the micro mill. I decided to keep my centerdrill in the same box as my 4 flute end mills. The box has a stiff plastic liner with nice indentations for each mill and a blank spot under the shorter ones. Just right for my stray bit.

So I pull the stiff plastic liner from the box and set it on the table of my mill thinking "Well, this is really just a big dremel tool. The slot's pretty small. I'll do it free hand."

So the 1/4 inch end mill goes in the chuck and I turn the speed down low and lower the bit into the virgin plastic.

Yup, I can see you wince from here. The bit goes in about 1/8 of an inch before it binds and rips the tray from my hand. The tray starts spinning and the end mills... did I forget to mention that I left the mills in their little slots?... well the end mills start leaving their little slots and shoot across the bench, clanking and clinking as I let go of everything and try to reach for the switch and stand back at the same time.

It seems that free hand and end mills don't mix. Even trying to use the side of an end mill to clean up the edge of a 1/8 inch thick piece of plastic ended in a mangled piece of plastic and an astonished look on my face.

The proper way to do it is to clamp it firmly to the table, possibly with a piece of scrcap underneath. This leave both hand free to operate the equipment (and shut it off) and virtually no chance that your project will become a spinning skillsaw wannabe.

Daniel


----------



## PEU

remember: think twice, do once /ubbthreads/images/graemlins/crackup.gif (not injured right?)


Pablo


----------



## gadget_lover

Naw, no injuries. I was aware that things might go wrong, so I was taking it slow. What suprised me was how well the end mill gripped the plastic when it siezed up. I was expecting it to be like using the dremel tool with a cutting bit. Instead it was like I'd bolted the bit to the tray. 

Yes, think twice, maybe even three times.

Daniel


----------



## Zackerty

I don't know that magnets are a good idea for holding toolbits for lathes. I use welding magnets to hold tools, and every time that I use the toolbits for turning steel, the tiniest fragments "stick" to the toolbit. The act of pulling off the toolbits magnetises the bits. The finish of the product can be marred by these " likkle mites" !!
As for things going wrong, look below the dotted line.....


----------



## gadget_lover

Boring bars are VERY necessary. I'm talking about the type that have a long bar and a bit. I recently found that you can use them in your mill as well as in your lathe. Who'd a thunk?

The bars in question.






So I ordered some from Harbor Freight to use with my HF 7x10 lathe. Item number 2456. A great price, only $17 for 5 bars. They ramge from 1 inch thick (12 long) to 3/8 thick (6 inches long). Should work great for doing larger flashlights.

Any one see a problem yet? I did not notice till I opened the box. I don't have 12 inches between the headstock and the tailstock. I will be lucky to be able to use the 6 inch long one. I guess I'll try cutting one of the the longer ones down.

Daniel


----------



## tvodrd

For boring in the mill, a boring head is the tool of choice. Lousy pic but they hold regular, round shank boring bars and they have a graduated micrometor screw to adjust the tool offset from the spindle centerline. They're expensive, but a "must have" for the mill. /ubbthreads/images/graemlins/smile.gif

Larry


----------



## gadget_lover

Knurling makes a nice addition to flashlights. It provides better grip as well as visual accents.

The proper way to knurl includes calculating the diameters for your work so that the teeth will track properly. If the teeth are 1/8 inch apart, the circumference needs to be divisible by 1/8. That provides a nice, clear pattern of diamonds 1/8 inch across.

So what happens when you throw caution to the wind?

I wanted to knurl an endcap. I only had a few minutes, as I was late to a party. I threw the knurler on the lathe and started turning. A funny thing happened. It worked, but the result was different from what I expected.

The teeth did track, but only after 3 turns. The tailcap has three sets of marks evenly spaced. I ended up with a very fine diamond pattern about 1/3 the size that I expected. It's very similar to what's on my ARC AAA uv.

If the teeth are 1/8 inch apart and your piece is not divisible by 1/8 but is divisible by 1/16, I think that you will end up with a pattern that's twice as fine.

When this happens, you can not make a deep cut, as the cuts will interfere with each other. 

Daniel


----------



## tvodrd

When knurling, I normally throw caution to the wind. When I did the different material CR2 lights, The tungsten and Ti bodies decided to multiple (very fine) knurl. The bezels didn't require any carriage travel, so I just ran the "scissor" tool across the part with the cross slide and they came out normal. I think matching the part diameter to be evenly divisable by the knurl pitch is necessary for straight knurls. Diamond knurls seem for me to track all by themselves most of the time. Unlike those with the smaller lathes, I have the advantage of being able to heavily-load my knurling tool. I recently bought an expensive tool (Dorian) which cuts rather than forms a knurl. I've only done one light with it so far and it came out nice. The instructions for it make no mention of matching the pitch to the diameter. /ubbthreads/images/graemlins/icon3.gif I'm still learning in the knurl department, but strongly suspect there is more art than science. What do you do with the ugly start and finish- you cut it away and call it "bordering." /ubbthreads/images/graemlins/grin.gif

Larry


----------



## gadget_lover

Bordering is actually the technique that I saw in the few tutorials on knurling.

Has anyone tried cutting DOWN the section they want to knurl by a few thousandths, then knurl it, then cut the border to the OD of the knurled section? I wonder if that will work to give a borderless knurl that looks good. Hmmm. Have to chuck up some scrap and try it.

I saw the dorian knurl cutter in a catalog. Does it work better? Does it make clean edges (unlike my cheapo knurls)? Does it take less pressure?


----------



## tvodrd

The Dorian tool actually cuts the knurl and the instructions have you calculate the depth (cross slide) for the cut based on the pitch of the cutter wheels. For the 30 tpi wheels, I think it was ~.012 deep. The forces required appear similar to those for turning, and they recommend similar speeds and feeds. I've only used it once and results were satisfactory. I don't have a pic, and gave the light away in Cambria. (See what you missed /ubbthreads/images/graemlins/nana.gif ) IMO the tool *might* work with a mini lathe (1/2H x 3/4W shank) but the damn thing costs more than a mini lathe. /ubbthreads/images/graemlins/faint.gif

Larry


----------



## gadget_lover

The problem; A threaded hole of unknown dimensions buried an inch below the surface of the gadget. I want to make a threaded adapter to fit in that hole. My thread guage will not reach far enough. I can't 'read' the threads because I can
only look straight down.

I've tried all my bolts and threaded rod, and nothing fits it. It appears to be between 7 and 8 MM. The gadget was made in India, so I suspect metric threads.

There are two solutions;

1) Drill out the existing threads and re-tap to a known thread

2) Somehow measure the threads

I was not sure if drilling out the hole would compromise the unit, so I pursued option 2.

I explored several techniques. I tried making self threading rods from soft materials, but none of them would actually hold a thread. I was considering dripping wax into the hole and teasing it back out when I realized I may have a solution;

Metric threads typically only use a few common pitches. Visually, it looked like .75 to 1.25 threads per millimeter. I put a nylon ziptie into the hole, then tried a 6mm x .75 bolt. The ziptie made a spacer that pushed the bolt against the threads on the opposite side.

The 6mm .75 bolt would only go in a few threads. I tried a 7mm 1.0 bolt. It threaded right in!

To get the diameter I simply inserted a tapered rod till it seated, then measured where the oil made a ring. That gives me the minor diam, so adding the double depth for a 1 mm thread (1.73 mm) gives me the major diam. It looks like the hole is for a 7.5mm bolt with 1.0 pitch.

Now all I have to do is test this theory by making the threaded adaptor. /ubbthreads/images/graemlins/smile.gif

* * * EDIT * * * This might have worked if the hole was properly threaded all the way to the end I was measuring. It was not, so my measurments were way off.
* * * END EDIT * * *

Daniel


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## KC2IXE

Measuring inside holes is an old problem, easily solved..

Get yourself some Cerosafe - interesting stuff - ulta low melting point - you pour it in, and it hardens, and then shrinks slightly - you remove it, and something like 1 hr later it's back to full size - now measure your perfect casting

Look at:

www.brownells.com - all sorts of good stuff


----------



## gadget_lover

Thanks KC2IXE. I'll look into that.

My trick did not work. I dis-assembled the gadget and found that it was actually 1.5 mm pitch. The hole was tapped from the other end, and part I was measuring was the tappered part from the end of the tap.

The post above has been altered to reflect the failure.

Daniel


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## gadget_lover

Someone asked 'can you do precision work on a Harbor Freight lathe?'


The common reply is yes, but you frequently have to adjust this and that to make it run true. 

I just turned a 5 inch long rod of 1.125 inch 2011 aluminum down to .900 inches. It actually measures .901 along the entire length. I'm so happy that the end stock and compound and ways are all properly aligned, and without my adjusting anything.

The silly newbie trick? I've done mostly small jobs, a few inches long. I crank the compound and cross-slide by hand except when threading, when I use the power feed. I just used the power feed during stock reduction and ended up with a great surface.

To use the power feed, you set it up for the highest gear ratio you can. In my case it's the gears 20-80-20-80 for 256 tpi. then you engage the lever at the back of the machine. I get a nice slow cross feed. For a 5 inch long rod, I was able to easily cut .20 at about 1000 rpm. The feed is super even so the finisj is exceptionally clean. At 250rpm it takes about 1 minute per inch.

The only gotcha is that you need to watch it as it gets near the end and disengage the feed so it does not run into the chuck or the shoulder of your work. This is a trick I read about, not one I made up.

Oh, trick #2; I used a silver Sanford brand marker to mark the number of teeth on each gear. This makes the molded in letters easy to see with out having to hold the gear just right. I also marked both sides of each gear so I can tell which is which even when upside down. This also helps when I forget what gears I have mounted. I can see the number on the back even if I can't see the front of the gear. 

Daniel


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## PEU

The phrase of the day:

*If you have a plan, stick to the plan...*

After drawing and redrawing to the slightest detail the wooden flashlight I'm building, today I began turning pieces.

Started with the head, I finished it in about 2 hours following to the minimum tolerances from the printed solidworks schematics.

This was about 5PM, happy with this 1st step done, I sat & relaxed for a few minutes and then started with the body part. 
Same process, knurling threading, everything going just fine, applying the *think twice do once* mantra I projected to be finished about 8PM.

About that time I finished the head side of the body, including knurl and thread, cosmetic borders, etc, and the magic moment finally arrived: I begin to insert the threaded head into the threaded body... they fitted like a glove, but it stopped about 5mm before the exact point.

I look at the head piece, the schematics and I quickly found the problem: between the end of the thread and the knurl (and in the middle the o-ring placeholder) the piece had the outside diameter of the thread instead of the inside diameter (as per the schematic)

Fixed this rechucking the head took no more than 5 minutes.

Then the WRONG decision ruined my head piece: after the last correction, the oring placeholder became too shallow, so I decided to make it a little deeper... I did it an the piece looked PERFECT...

Removed the piece from the lathe and began to screw it into the body when I feel the crack... my right arm holding the knurled part and inside the body, the threaded part 

The o-ring placeholder is the thinnest part of the head, when I deepened it about 0.7mm more I eated almost all the wall... and not, this wasn't in the schematic... /ubbthreads/images/graemlins/jpshakehead.gif

Tomorrow, I'll do it again /ubbthreads/images/graemlins/banghead.gif


Pablo


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## tvodrd

Pablo,

Trust me, that sort of thing is _normal!_ (Happens to me all too often. /ubbthreads/images/graemlins/frown.gif )

Larry


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## gadget_lover

I'm so sorry to hear that Pablo. 

If it helps, I did the same thing with a head I was making, except I decided that I needed to bore out a depression inside the head (to fit the converter) 1/32 inch deeper. This took me right into the threads I'd cut on the outside, very effecively parting it in the middle.

But think of all teh good practice you are getting /ubbthreads/images/graemlins/smile.gif

Daniel


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## rwolff

[ QUOTE ]

I would think that those magnetic tool holder strips wold be useful above a lathe and want to get one when I remember to! I see it as a temporary spot for holding the tools in use at the time; drill bits, end mills, QC holders and the like.


[/ QUOTE ]

Do you *ever* plan to use your lathe for ferrous metals (i.e. steel)? If so, you'll never get all of the chips out of those magnetic holders.


----------



## gadget_lover

OK, here's one I learned from Harry N.

Suppose you have a flashlight with a head that screws on. It butts up against a lip of some sort. There's almost always some slop in the threads. This can cause the head to screw on straight but still not line up perfectly with the body. It can be off by whatever slop you left in the threads.

Harry's trick: make a slight bevel on the side of the lip and a matching cut on the other. 5 or 10 degrees is enough, and the female part should have the same angle or slightly greater than the male part. The bevel will center the part as it comes together.

Here's what I mean. The angles are steeper than they needed to be. The middle picture shows the two halves just meeting, the last is fully screwed together. I did nothing to hide the seam, but worked it into the general look of the light.


----------



## gadget_lover

So there I was, working on a tailcap. I was using a design where the flashlight body had male threads (outside) and the tailcap had female threads. I wanted to add an o-ring, so I added a skirt to the tailcap that would cover the o-ring. I was putting a clickie in it from another light.

It was to be .85 inches long.

I had about many different steps to do, so I reduced the stock to .030 larger than the body of the light. I then drilled it the diameter of the switch (1 inche deep). Then I bored out the first 1/4 inch for the skirt, The next 1/3 inch was threads, So I bored that and then threaded it using a single point tool. I got the depth exactly perfect on the first try.

Then came trouble. I wanted to camfer the edge, so I switched tools and moved the carriage to the end of the tailcap. I got the angle I wanted and locked everything down. For extra rigidity, I flipped the lever to engage the threading halfnuts. I turned on the switch. 

Imagine my suprise as the carriage started marching towards the left, fractions of an inch from munching my newly turned tailcap.

I stoppped it just in time. I had left the threading gears engaged and didn't notice.

Newbie trick 1)
I'll be adding a stripe of paint to the threading lead screw so there will be sometjing in my line of sight to remind me that it's turning. 

Newbie Trick 2)
Some threaded parts never feel tight enough. When setting up the tailcap, I designed it so the tailcap seats against the end of the flashlight body before it ran out of threads. Threads on body .3 inches long, Threads in the tail cap are .25. The shoulder is just beyond the threads. If anyone needs pictures I can provide them.

Daniel

Daniel


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## PEU

[ QUOTE ]
*gadget_lover said:*
Boring bars are VERY necessary. I'm talking about the type that have a long bar and a bit. I recently found that you can use them in your mill as well as in your lathe. Who'd a thunk?

The bars in question.





So I ordered some from Harbor Freight to use with my HF 7x10 lathe. Item number 2456. A great price, only $17 for 5 bars. They ramge from 1 inch thick (12 long) to 3/8 thick (6 inches long). Should work great for doing larger flashlights.

Any one see a problem yet? I did not notice till I opened the box. I don't have 12 inches between the headstock and the tailstock. I will be lucky to be able to use the 6 inch long one. I guess I'll try cutting one of the the longer ones down.

Daniel 

[/ QUOTE ]


How these worked Daniel? I need a boring bar solution, by far, the most time consuming task Im doing these days...


Pablo


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## gadget_lover

I've not yet had a chance to use one. I forgot to order a boring bar holder for my tailstock the last time I went wild with the Enco Catalog. They are too big to use with the 7x10 in most cases.

Daniel


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## gadget_lover

Yup, it's me again. /ubbthreads/images/graemlins/smile.gif


We are going to talk inserts.

I was trying to turn a 1 inch bar of steel today and learned something about inserts. I seldom turn steel, so I was leary about it.

I was trimming down a 1 inch OD hardened steel MT2 adapter. I wanted to cut off the end cleanly so that I could use it as a collet closer on my 7x10 HF lathe. The adaptor had a closed end and was designed for MT2 collets with tangs. I chucked it and used a live center in the tailstock for added rigidity. I could not get my cut-off tool to bite into the steel so I thought I'd just use one of my lathe bits to cut through it.

I used the 3/8 inch indexable tool holder that I got from harbor freight a while back. The insert was the same one that I've used to cut a lot of aluminum. I was able to barely get it to cut the steel, and had a very rough surface where it did cut in. I decided it must be dull.

Before giving up, I remembered that I had some TIN coated inserts that I'd never used. I'd selected it scientifically at the supply store by visually comparing their stock to one of the HF inserts.

The new insert cut the steel like it was aluminium. I was able to run the carriage left and right a bit (1/2 inch), then advance the cross-slide .020 and do it again. In no time I cut all the way through, ending up with a nice flat end.

OH, the stupid trick? I was concentrating on where I was cutting and seemed to hit a hard spot where I could not advance the bit any more. I finally noticed that the right hand side of the cross slide was pushed up tight against the tailstock. That's why it would not move.

Daniel


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## rwolff

[ QUOTE ]

Before giving up, I remembered that I had some TIN coated inserts that I'd never used. I'd selected it scientifically at the supply store by visually comparing their stock to one of the HF inserts.


[/ QUOTE ]

By "visually comparing", are you referring to insert size and shape, or to some other property? If you mean size and shape, all standard sizes of inserts follow a code. There should be a code printed somewhere on the box (inserts normally come in a box of 10) - if you post any "funny" alphabetic (or alphanumeric) codes from the box, I can describe what your insert looks like.


----------



## gadget_lover

There are numbers that you can decode, but I did not know that at the time. The Machinery's handbook has a section on it.

The size and shape were all we compared. I bought 4 from a box of 10, didn't get the box. There are specific angles and such that should be used for various materials, but I've learned that you can fudge a lot.

Daniel


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## PEU

This time the silly newbie trick is regarding ORings.

After around a month of trial/error tests for the orings in my current project (NEOCA BL) I decided to ask the experts /ubbthreads/images/graemlins/smile.gif

And this is the answer I didn't expect: 

there are two classes of oring placeholders

Moving applications (like our twisties)
Static applications (the part will not move)


Searching online I came acrosss this site that automates the process:

Moving: http://www.sealseastern.com/OringRodSeal.asp
Static: http://www.sealseastern.com/OringPlugSeal.asp

A quick test gives that for static the oring compresion is around 20-30% of the section, and for moving parts (twisties) the compresion is around 10-20% of the oring section. Same results give the width of the placeholder at 130% of the section.


Pablo


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## gadget_lover

Thanks for the O-ring info Pablo. All of that was new to me. I've not even come close to selecting correct o-rings.


Now for the silly newbie trick.

I have a 7x10 lathe, which does not really have 10 inches between the chuck and the tailstock. That's OK, because I knew that when I bought it. The only times that the short bed is a hassle is when I'm trying to drill something that's in the head. Before I bore, I usually drill to close to the desired size.

The problem? The drill chuck protrudes several inches from the tailstock. The work protrudes several inches from the chuck. The drill protrudes several inches from the chuck. A large drill protrudes 5 inches or so..... Oops. No room left!


The solution? Some folks cut off the drill to make it shorter, then resharpen it. Some folks buy drills with an MT2 taper on the shaft, but those are expensive. I have used MT2 collets from www.littlemachineshop.com in the tailstock to hold the larger drills with some success. The collet protrudes just 1/2 inch from the tailstock quill. The taper holds the tool firmly. To remove the collet you simply use the handwheel to pull the quill all the way in. The lead screw that moves the quill pushes the collet out.

A morse taper is supposed to hold itself in. To seat it firmly, I use the 14mm open end wrench as a drift to firmly seat the collet in the tailstock quill. The 14 mm wrench fits over the 1/2 inch shaft and tapping it with a light tack hammer makes sure I don't over-do it.

Here's a comparison of two drills that are the same length. The one in the back is arranged in about the same position it would be in if it was in the tailstock. The tailstock is almost off the end of the ways. 









This close up shows the drill in the collet. The drill's shank goes almost all the way down to the end of the cuts, about 1.5 inch. This is a "Silver and Deming" drill with a shaft that's cut down to 1/2 inch diameter.





The 1/2 inch shank of the drill in the collet is much more rigid than the 3/8 inch shank of the drill in the chuck. 

A note of caution; if the drill bit hangs up in the work it is more likely to be pulled out of the collet, or the collet is more likely to be pulled out of the taper than would be the case with a drill chuck. On the other hand, if the only alternative is to use a hand drill or drill press.....


Daniel


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## tvodrd

Drill bits are available in 4 standard lengths X 4 diameter ranges. "Screw machine" (shortest), "Jobber" (your local hardware store) "Taper length" (it varies by size, but think 6" OAL for a 1/4" bit) and "Aircraft" (typically, 12" long) This is olde-nomenclature, and may not match current catalog designations! Drill diameters can be had as Number drills #60 (.040") - #1 (.228" dia), (yeah they make 'em much smaller!) Letter (A=.234"-Z=.413"). fractional (1/64- x 64ths to sky's the limit) and metric. A drill bit typically will produce a hole that is slightly larger than its size. (I'll spare you Reamers and what to do with 'em. /ubbthreads/images/graemlins/grin.gif ) Most of the suppliers will sell you indexes with #'s 1-60, Letters A-Z and Fractionals 1/16-1/2" They are a good investment. Learning to sharpen a drill with a bench grinder is one of the most basic skills a machinist must aquire!

Larry


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## KC2IXE

There are also Morse Taper drill bits - yep, they have the taper right on the tank - yet another option. I have a few of those floating around, and back when I worked in HEAVT industry, we probably used them more than anything else (had drill presses with 5MT shanks). It was strang working in a place where 1/4" drill bits were like #80 bits are in most places - "tiny". We worked with drill presses that, like most, could pick up and spin the work - only in the case where I saw the guy NOT dog the work, it was a 10 ft long piece of 6" wide flange beam - as in stuff you use a crane to move around


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## gadget_lover

Did you need a drawbar with those 5MT shanked bits, or were they just held by the taper?

I can't imagine the impact of a 10 foot beam swinging through the air. Yuck.


Speaking of "swinging through the air". I had an unusual experience last night as I was turning some aluminum on my 7x10. I been reducing a rod of aluminum by 1/4 inch and had a pretty fair sized pile of shavings in the splash-guard behind the ways. A curl grew from the cut and somehow caught on one of the chuck jaws.

In a split second the errant curl caught in the pile behind the chuck and pulled it up and around the piece I was working on. The piece was turning around 1000 RPM. Shavings flew everywhere! I had them in my hair, my pockets, everywhere. 

Lessons learned;

Glasses are a VERY GOOD thing.
Clean out the swarf more frequently.

Daniel


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## HarryN

Gee Daniel - sounds like you had a grand time!! My brother tries to avoid this situation by keeping a small shop vac turned on all the time sucking up at least some of those shavings while the work is going on. Glasses of course are still a must.


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## PEU

Yeah, it happened to me too, all of the sudden I look like a 70's disco machinist!!! all my hair with aluminum /ubbthreads/images/graemlins/crackup.gif

In my case just for being too enthusiastic, and dont make a few seconds to remove the shavings aside at least.


Pablo


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## KC2IXE

No drawbar on those MT5 drills. BTW I've been told that MORE people are hurt with drill presses than any other machine in the shop

Of course the machine that got the greatest respect in the shop was the old style (flywheel) ironworker - those are a machine that can HURT you FAST. Ever wonder how you put holes in the flanges of an I beam quickly? You PUNCH them - nice 3/4" holes in the 1/4" or 3/8" flange as fast as you can say "Bang". Pick up the beam with the crane, align it with the punch, lower the punch, make sure everyones hands are clear, and step on the foot peddle. About 1/2 second later you have a nice hole in the flange. Reposition the beam, and do the next - takes a couple of minutes to do both sides and both ends, including putting the beam down and flipping it


----------



## gadget_lover

***Sneeze*** Ewwwww!


I usually cut aluminum on my lathe. I have a nice stockpile of various aluminum stock, but very little steel.

Last night I was altering a steel backplate for a 4 inch chuck that I bought for 
my 7x10 HF lathe. Of course I faced it, knowing that I wanted to make everything concentric. I had to cut out a .155 inch deep recess to fit the spindle flange, then had to do it a second time when I got the first one too wide by 10 thou. 

Being a 7x10, I had to take fairly small cuts, generally under .010 inch, often about .005. Even so, I stalled it a few times. I did not see a lot of dust, but my fingers were black by the time I'd finished the first side. I have not done the second side yet.

The Silly Newbie trick? I cut it dry, since the cutting oil smoked pretty badly as the chips flew. I appear to have created a lot of very fine dust. So much dust that, when I sneezed the tissue turned black. Yup, I shoulda worn a mask of some sort to catch the dust. I've still got some black stuff coming out of my nose this morning. Ewwwww.


Daniel


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## wasabe64

Yep, cast iron is nasty stuff to cut dry. I hope you're okay. 

I used a water-based flood coolant in a spray bottle when I cut cast iron (same purpose, the backplate). Keep a pile of rags under the bed of the lathe, and wear an apron or smock if you have one. 

The kicker is that there is some dust even when you cut wet, so your mask suggestion is a very good one.


----------



## gadget_lover

Yeah, I'm OK. The nose is even normal again.

I'd always thought that the pictures of iron workers with black hands related to their working with grease. Now I know better.

Daniel


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## gadget_lover

Every once in a while I'm doing long things that don't fit through the lathe's headstock spindle. The spindle through hole is just less than 3/4 inch. Normally, you could attach the tailstock and mount a live center to support the bigger item as you turn it. That keeps the item from flexing as the bit presses against it.

My lathe has less than 10 inches (more like 8) between the tailstock and the chuck. Obviously a piece longer than that (a model cannon, for instance) will not fit.

One solution is to use a steady rest to support the far end of the work instead of the tailstocck. The steady rest mounts to the ways like the tailstock does.

If you've never seen a steady-rest, here's one from little machine shop. Ignore the fact that it's listed as a follower rest.
http://littlemachineshop.com/Products/images/1197.jpg

Daniel


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## PEU

I have one!, it came with the lathe, and as you said, very usefull when working with long rods.

My tip about it is to use oil in the part where it touches the follower rest, that way you scratch less the part.

What I really never used to date is the follower rest, which I also have.


Pablo


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## gadget_lover

I'm pretty sure the best use for a follower rest is for thin stock that might move away from the cutting bit. A 6 inch long 1/4 inch aluminum, for example. A follower bolts to the carriage, so it moves with your bit.

Thanks for the oil reminder, Pablo. It's possible to retrofit the rest to use bearings instead of teh bronze rubbing blocks. Little Machine Shop has one listed in their catalog.

I've not used the follower rest, though I bought one from HF when I bought the lathe.

Daniel


----------



## OddOne

I've already found a few things out even though I've only had my lathe for a few weeks now.

Some test goodies:





For starters, I use the "never release the powerfeed - just wind in a couple thousandths, cut, wind out, reverse, rinse and repeat" method of threadcutting and can make a pretty nice set of threads without using a die. A brief followup with a finishing pass to add the flats called for in UNC/UNF threads, and the result threads into premade nuts without binding.

I also found out about the metal-weedwhacker syndrome while parting off some 1/4" rod. To compensate I put a little oil on my hand and hand-supported the rod end poking from the headstock, and ran the lathe at very low speed. Not exactly the safest way to do it - we are after all talking about holding a spinning metal rod in your hand - but it worked well.

Experiments with tailstock-chucked drill bits showed me that if I'm patient and center the matieral properly I can bore out a rod to leave a 1/32" wall thickness on a knurled part. Of course, one should do the knurling pass before the drilling/boring one. /ubbthreads/images/graemlins/wink.gif

Found out that I needed to part off about a half-inch of my tailstock chuck's taper so it'll stay in the tailstock with it wound in to zero. So, I tapped the arbor out of the chuck - it was a rather basic Jacobs #3 to MT2. Ever tried to chuch a tapered part? More to the point, ever tried to CENTER a tapered part? I cheated though - I wound the slide all the way in, making sure the toolpost cleared the chuck, and used the tailstock to crank the arbor into the chuck. Tightened the chuck and then backed off the tailstock, and the arbor was perfectly centered. Parting off that hardened-steel arbor was time-consuming, but the result was rather clean.

Also found a way to face a part easily, quickly, and smoothly. First, I mounted the facing bit so its cutting edge was properly centered on the work. Then I gradually brought it against the work with the tip slightly PAST center. Slowly, of course, so it would take off any rough material from previous cuts. Next I alternated the process of backing the slide out and cutting back into the center, while maintaining light pressure against the material with the carriage handfeed. The outward passed took a LOT of material off smoothly, and the inward passes squared up the face. When it's properly cleaned up, I stopped applying pressure on the inward pass so the finished result was square. I took a tenth of an inch per out-then-in pass on 1/2" cold-rolled steel that way, and the end result was nicely smooth.

More as I think of it...

oO


----------



## gadget_lover

Hey odd-one, nice work there!

I'd caution you against hand supporting the stock sticking out of the back of the headstock. It will probably work well much of the time, but that's a bad way to locate a burr, say one left from a previous chucking. A 1/16 inch strip cut all the way across the palm sounds like a pain. (No pun intended).

I've heard of using a loop of rope to contain the oscillation, and also the use of a PVC pipe as a 'guard'. At the very least you'd want to use good gloves if supporting the stock by hand.


Daniel


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## OddOne

Yeah, I was saying under my breath WHILE DOING IT that I was being idiotic and had only myself to blame if I took off a finger. I did check the rod for burrs first though.

After that I used a cutoff wheel in an air powered die grinder to lop off an oversized piece, shortened/faced both ends, and proceeded.

oO


----------



## gadget_lover

I thought I'd share my latest trick.

I was finally turning some new flashlights on my lathe. I have not been able to use it much this last few months. All was well as I roughed out the shape of the light. Suddenly, just as I was going to make the last pass, the carriage stuck about 1/2 of the way down the bed. It would move to the right, but not the left. I suspected that there was swarf in the gears that connect the carriage handwheel to the rack under the ways. I'd read about that happening.

I looked under the iron casting, and sure enough found metal chips in the teeth of the gears. There's no cover over the gears to prevent shavings from accumulating there. I'd read about how easy it was to add a plastic shield. I pulled out the manual, read up on it online, and started disassembling.

The cover came out real nice. I cut a 1/8 inch acrylic sheet from tap plasticon my woodcutting bandsaw. I got it perfectly shaped. Glue was supposed to work, but I decided to go with screws. I drilled and tapped the cast iron for 6x32 screws. It looked real good when was done with it. Too bad it's not visible when assembled.

I cleaned and lubed everything (white lithium greese), and it went back together without any problems. No parts left over this time. I was quite pleased. It took less than an hour.

I turned the handwheel to enjoy it's silky smoothness. It stuck. At the same spot. I examined the teeth on the rack for a minute. Then, and only then, did I look at the top of the bed. 

Do you see why it was hanging?







I should have realized that the DRO was hitting the live center. It had happened before. I was watching the bit so intently that I did not look at the other end of the compound. It was so simple... 

So the neat thing is that there's lots of room to add a chip shield under the apron that holds the handwheel gears. It's an easy upgrade and I'm glad I did it. It also gave me a chance to center the apron so the threading half-nuts are
concentric with the leadscrew. The apron can move in and out, and if it's off center the lead screw will be pulled to one side or the other when you close the half-nuts.

Daniel


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## gadget_lover

*Yes, At no extra cost you too can add not 1, but 1 and a half inches to your...*


7x10 mini lathe.

Problem: You want to turn a 7 inch long C cell battery tube. The bar you will be turning on does not fit through the body of your chuck. You discover that your carriage will only travel 5.25 inches from the chuck to where it runs into the lead screw's pillow block. Yikes!

By the time you add in the width of your tool post and tool holders, you've lost some serious length. You are down to 4.75 inches from chuck to end of cut when using a TS engineering quick change tool post with the tool mounted on the left side.

You can add almost 1.5 inches by removing the threading indicator. The theading indicator body is only 7/8 inch wide, but it prevents the pillow block from sliding behind the apron.

If you then spin the tool post 180 degrees and re-mount your tool, you will gain another 2.75 inches. You'll have to re-calibrate the tool to get the same depth of cut if you do this.

The first photo shows the pillow block hitting the indicator. The second shows it behind the apron. The third shows the extra inch and a half without the indicator. The last shows what you get with the tool post reversed and the pillow block removed.





















Yes, that last picture shows 9 inches from the chuck's jaws to the point of the tool. With the tool on the right of the QCTP, you may not be able to move the carriage far enough to the left to cut near the chuck. The protruding chuck jaws will hit the compound if you are not careful. That means you will have to swap the tool midway through the cut. With the tool on the left of the QCTP you loose a touch over 2.5 inches. 

Using the tailstock may also stop the carriage before the pillow block gets in the way. Take that into account when planning your project.


Daniel


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## gadget_lover

I added a 4 inch chuck to my lathe. I had to make a backplate for it. It is possible to make a backplate that big with only a drill press and a mini-lathe.

Key learnings;

o It's hard to get the tool bit (on a HF 7x10 lathe) to the outside of a 4 inch plate. Two techniques came to mind. First was to turn the tool post all the way around so the tool bit was mounted on the other side (nearest you). The other trick was to rotate the compound to about 30 degrees so the left side was closer to you. That gave more than an extra inch clearance.

o When altering an existing part, plan out the whole thing (and mark it) before you start turning. Make a list of what order you will do yourt cutting, so you can be sure that it will all work. My adapter started out looking like this




It ended up as a 1/2 inch thick plate with a recess on the left and a shoulder on the right with appropriate holes to mount the chuck. Here's my original chuck and my new one holding the same 1/4 inch bar. /ubbthreads/images/graemlins/smile.gif





What I needed to do was:
turn a recess on one side to match the lathe's spindle.
turn a shoulder on the other side to match the recess on the chuck.
add threaded holes for 4 mounting bolts that attach to the spindle.
add a second set of 4 holes to attach to the chuck.
mill a recess around the chuck bolt holes for the head of the cap-screws.
ut a 2.5 inch diameter threaded nose off one side of the adapter.


*I did it all wrong*.

I only did rough estimates of where things should be cut. I turned the recess matching the spindle on the wrong side because I clamped the threaded nose in the chuck. I drilled the holes for the spindle mounting studs just .020 too close together, then tapped the holes at a slight slant. One or the other would have been OK. Both were too much. I had to drill new holes 45 degrees offset from the originals and tapped them straight using the information in the 'tap and drill' thread. The bad set were filled with JB-Welds epoxy and smoothed over.

After cutting off the 2.5 inch threaded nose (thank goodness for the poratble bandsaw), I was left with a 3/4 inch thick steel disk with 3 9 mm holes in all the wrong spots. Oh, the holes had 11 mm wide recesses around them for the heads of the bolts... on the wrong side. I could have added 3 more holes, reusing one of the originals if I'd turned the spindle recess on the other side. I ended up filling all 3 of the holes with JB-Weld epoxy and starting over in different spots. It was hard to find 4 spots to drill without hitting one of the original holes.

*What I should have done* was cut the nose off first, that's the side that would eventually go against the lathe's spindle. After that drill 7 holes; 4 for the spindle, 3 for the chuck. Add clearance holes for the cap screws. Tap the 4 and use them to hold the plate against the spindle while that side is faced and the recess is cut. Flip the plate, face this side and cut the shoulder to match the chuck. At that point it's centered, all holes are drilled and ready to go.


o When you think you see something slip, remeasure the set-up. I was drilling the mounting holes on a rotary table and thought I saw the disk slip just a touch. I checked it by tugging, and everything was tight. I later found the last two holes were .030 off from where they should be. The disk had slipped. If I'd checked with the dial indicator I would have detected the slippage.


o Don't be afraid to toss it and start over. I was not able to run down to the metal supply place to get a fresh blank to work with. If I could of, I would have saved hours and hours.

Was it all worth it? Yeah, it was.

Daniel


----------



## OddOne

My newbie trick:

Making a bezel, right, the first time. Pic for illustration:






The process is making matching outside and inside threads is described as a p.i.t.a., but this saves umpty beaucoup time compared to doing the measurements & math...

For my description I'll call the parts male and female. The male would be a flashlight head, let's say, and the female the bezel ring. IOW, like a connector, male goes into female and female goes onto male. I'm sure you can read any amount of sexual innuendo into the descriptions to follow, but let's keep it clean. /ubbthreads/images/graemlins/wink.gif

First, create the male part as per your design. Measure up and prepare the area to be threaded and provide at least one runout area on the end of the part, cut to JUST DEEP ENOUGH to not be touched by the threading tool when you cut the threads. The runout only needs to be an eighth-inch or so wide, so you could make it wider and use it for an O-ring land, etc. as well. (You could add the runout after threading, for example, but this will likely mean needing to clean up the first thread turn.) Provide a runout on the inside end of the threaded area as needed, although this is optional. Thread the male part as desired, and use a gauge on it if possible/available to make sure you formed the threads properly - for UN threads you want a crisp 60-degree vee with a sharp valley, smooth thread walls, and very little to no flats for thread peaks. You want the male part's threads to be perfect because you'll be using them to gauge the female's.

By creating the runout area on the end of the male part, you're also creating a gauge for precisely how big to bore out the female part. So, do so, and check to see if the male part's runout area JUST fits into the female part after every few thousandths' worth of boring. It should be a tight enough fit that the male part doesn't exhibit any free play, but not so tight that it'll get stuck.

When this is achieved, create runouts inside the female part as needed and thread with a matching TPI setting. Once you get the threads close to finished, check the thread compatibility by trying GENTLY to screw the male part into the female after every couple thousandths' worth of threadcutting, and stop when you cut the female threads well/deep enough that the male part threads in smoothly and without interference.

Once you're at this stage, cut the threads a smidge deeper if the parts will be anodized, etc. to account for the additional thickness the anodizing will create, and you're done. Perfect fit on the first try.

oO


----------



## gadget_lover

Today's project was to build a binocular mount for my tripod's quick release. This involved machining a rectangular block with dovetails cut on opposite sides. The dovetails are 60 degrees, and I have dovetail cutters for my mill, so I was in business.

*The newbie problem*; Measuring the dovetail depth accurately so the dovetails matched the original and each other.

Measuring dovetail is difficult, since the width of the caliper jaws means you don't measure exactly the same spot in each cut. The V groove of the dovetail causes the jaws to hit somewhere other than the deepest part of the groove.

The vertical height of the cut was easy, I just measured with a digital caliper. The depth was another issue. I tend to cut the dovetail too shallow or too deep, and this was not a case where I could test fit the tripod to the mount without removing the mount from the mill.

I took the basic technique from the Machinery Handbook's section on cutting dovetails. That section tells you how to use trigonometry to calculate the correct width of a part with dovetails. The technique includes putting a rod of known diameter in the dovetail to provide an easy and consistant reference point for measuring.

*The trick*
I was duplicating an existing mount, so I used the rod trick to measure the old part and used that measurement when I cut the new part. No math needed!! /ubbthreads/images/graemlins/smile.gif 

The pictures below show how I measured the old and new part. The old one is the black plastic one. The rod was just a 1/4 inch brass tube pulled from a grab-bag. It was the same diameter at several spots along its length, so it was good enough. The block was 1.540 inches across. 

I first milled the block to the same size as the original. Then I marked the cutter height with a line and adjusted the mill till the cutter just barely hit it. I ran the cutter across the face, cutting .030 to .005 per pass. I stopped when the caliper showed the same measurement (1.684) as it had on the original.

I measured from the side of the tube to the back of the block for the first dovetail. I used two tubes for the second dovetail.












The end result was dovetails that matched perfectly on both sides. Oh, the quick release mount was a success too!


Daniel


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## gadget_lover

Calipers, Calipers and Calipers.

I use the cheap digital calipers a lot. You can get a 4 inch model from HF for under $15 when they are on sale. You can get the 8 inch model right now for only $22.99.

These are very versatile units. If you don't have one you don't know what you are missing. They measure in MM as well as inches. Everything is decimal so there's no need for fractions. They actually measure in at least 4 different ways.

It's important to clean the jaws before using (I swipe my finger across the edge) to clean off any grit or shavings that may change the readings. Make sure the part is square and that the caliper is not tilted when you make readings. Always zero the caliper before use, especially if changing from one use to the other.

*Outside*
First, the large jaws measure the outside of things. A few tips to help when doing outside readings. First, the jaws on the 6 and 8 inch models are longer than the 4 inch. The jaw length limits the maximum diameter that you can read. Second, if the part you are measureing is not sitting squarely, your readings will be higher than they should be. I usuually wiggle the piece being measured to see if the reading will decrease. Third, the area of the jaws nearest the body has a slight cutout. I think this is to allow you to get beyond rough edges when measuring.








*Bevels*
Measureing things that are at an angle can be a hassle. Measuring dovetails are even worse. The problem is deciding where to measure and being able to repeat a measurement. The dovetail is a special case of this problem.

A quick background on dovetails: A dovetail is a slot with sloping sides that is cut to match a protruding part. It provides a very secure mount that can slide back and forth. Dovetails are often 60 or 45 degrees and you can buy milling cutters at that angle for under $10.

The trick for consistant measurements of a dovetail is to use a pair of rods that are small enough to rest against the sloping part of the dovetail. That's the critical distance in most cases. If two parts have the same depth and the same distance between the rods you should have interchangable parts.







*Ledges*
Ledges? Ledges??? We don't need no stinkin.....

Sorry. Got carried away there. It's not always easy to accurately measure from the edge of a piece to a raised section or ledge. I kept trying to use the outside jaws, holding one edge against the jaw and eyeballing it till it looked right. That seldom worked.

Your friendly caliper is already set up to measure such ledges. You use the back of the caliper. The end of the caliper body and the end of the moving part meet exactly. Simply open the jaws, set the head against the ledge and slide the jaws closed.






*Inside*
Measuring inside openings calls for using the small jaws on the back side. The only trick I've discovered there is to move the jaws until you get the _largest_ possible reading while the jaws are parallel if the opening is circular. Use the _smallest_ possible if it's a flat sided opening. 


*Depth*
Your Caliper also measures depth. The little tang on the end that always gets in the way is, in fact, a depth guage. To use it, you open the jaws so the tang sticks out, then position it at the edge of the piece. Push the end of the caliper against the edge of the piece. YOur reading is the amount of tang that's still sticking out.

Here I am checking the height of a round piece that's clamped in place.







Daniel


There's more, and I'll post that in a bit.


----------



## gadget_lover

Caliper mods.

Yes, I can't leave well enough alone.

The cheap calipers from China are very useful, but sometimes you can make them more useful.


Look at the picture just above this post. It shows a 4 inch caliper that's actually almost 7 inches from end to end. While it fits well in the hand and works well for most things, I frequently have a problem checking measurements while the work is in the vice. The other end hits various parts of the mill.

My answer? The Shorty. I cut almost 3 inches off the end of a standard 4 inch caliper, leaving it capable of measureing 1.25 inches. It's now just 3.5 inches long.







If you try this, remember a few things.
1) The metal is hardened. A hack saw did not like it, my power bandsaw took forever. The cut-off wheel on my dremel was much faster but messier.
2) The black plastic can be cut through without harming the tool.
3) I needed to use carbide bits to drill the tiny holes that are needed to mount the stop at the end. HSS drill bits would not touch it.

And here's shorty at work.






Daniel


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## gadget_lover

Calipers. Can't work witout one.

Sometimes you don't really need all 4 measuring tools in one. Sometimes the extra features get in the way. This is espcially true for those of us using mini lathes and micro mills. When I use my caliper on a piece mounted in the lathe chuck, I have a 50-50 chance that the tang will hit the tailstock.


A pair of bolt cutters made short work of the tang. It's cut off about 1 inch from the carrier, so it still guides it well enough.

Other mods have included cutting off the inside jaws (smaller ones) so they don't interfere with outside measurements.

As you may have guessed, I bought 4 or 5 of them when they were on sale and have made several of them single purpose tools.

Daniel


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## gadget_lover

Ok, last one for a while.

Part of learning to machine is to do proper setups. Measuring, marking, etc. Unfortunately, the proper tools get expensive quickly.

Here's a quicky stand that helps make a straight line to tell you where to stop cutting, start drilling, etc. All it takes is a block of wood, a clamp and a caliper. In my case, a 6 inch digital caliper.


The first photo shows a simple setup. I clamped a caliper upside down to a smooth wooden block. By lowering the jaw to the surface of the wood I can press zero and have an instant height guage or marking setup. In the picture I have painted a piece of scrap with blue dye and then turned it while it pressed against the tip of the caliper. That left a nice straight line .182 inches from the end of the scrap.






I liked that, but decided to make it more repeatable, since the edge of the wood barely touched the caliper's jaws. That made zeroing it iffy. A quick cut with a saw gave me a slot for the caliper. The cut is shallower than the jaw so the top jaw can rest against the surface of the wood for zeroing it. A clamp squeezes the wood and holds the caliper firmly. Here's version two. It's sturdier, better zeroing and allows the work piece to be supported on both sides.






When I get a round tuit, I'll make a stand from aluminum. The caliper was not harmed at all and can be removed for other uses.

Daniel


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## tvodrd

Daniel,

Next you'll be getting a height gage and surface plate. The granite surface plate in the shop at work is 4' x 4' x 8" thick, and they are available a lot bigger than that! /ubbthreads/images/graemlins/grin.gif

Larry


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## gadget_lover

Now, now Larry. don't you go making the others envy you. A proper shop like yours must be a breeze to work in.

Now that Larry's brought it up, I've seen height gages and surface plates in the Enco sale catalogue at reasonable prices. My granite surface plate is only 9x12x2 and I think it was under $20 on sale. I didn't think I needed a height guage at the time. Guess I was wrong. /ubbthreads/images/graemlins/smile.gif


Daniel


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## tvodrd

You're one-up on me! /ubbthreads/images/graemlins/grin.gif (I don't have a surface plate at home, /ubbthreads/images/graemlins/frown.gif and have been _improvising_ for years.) a good "flat" is ideal for lapping Luxeon slugs and heatsinks! A "real" toolroom guy would choke-my-lights-out if he saw some of the things we have done on the once-calibrated one at work! /ubbthreads/images/graemlins/icon15.gif

It's probably been covered, and I see Daniel is up to speed with using lay-out dyes like Dykem. You paint or spray it on, and it quickly dries. You can then scribe lines for locating for holes, etc, and be able to see them more clearly. Some high-end calipers, and most height gages have brazed carbide outside jaws to extend their lives when using for scribing. I have a couple of the HF 4" dial calipers, and wish to hell Mitutoyo would copy them! (I hate _digital_ calipers! /ubbthreads/images/graemlins/grin.gif ) 

My home shop has a long way to go. (Daniel has seen it.) I have to swap plugs to huff-up the compressor, and I badly need another tool chest and time to sort out all the tooling- I keep losing stuff I know I have. Unfortunately, I can't afford to retire, yet. /ubbthreads/images/graemlins/frown.gif

Larry


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## gadget_lover

I can't believe we haven't really discussed Dykem in this thread!

Layout dyes are used to mark off the area where you will cut. Because you can see where to stop, you don't have to stop and re-measure every few passes to avoid over-running your target depth. Layout dyes work on the lathe as well as on the mill. It can also be used when hand filing or drilling.

As Larry said, Dykem is brand name for a blue layout fluid that does NOT stain metal. The fluid brushes on and dries in a matter of seconds. It's thick but not brittle. Dragging a tool across it leaves a nice, easy to see line with the underlying metal shining through. This works even when the metal is too hard to actually scratch. Protractors make nice arcs in it, a nail or scribe will leave a clean line. The points on the caliper also work well. 

Dykem is available in blue and red, and possibly other colors.

The companion to Dykem is the Dykem remover. It's a spray that cleans off the dye as well as oils and other dirt. A quick spray and the dye just sluices off. A 4 oz bottle of dye and a 12 oz can of remover cost less than $10. The blue coating in the post above will disappear in a moment.

Don't let Larry's modesty fool you. If my lathe bed needed truing, I could mount the whole machine on his mill. If I needed to bore out the headstock of my lathe, I could chuck the whole thing in his lathe! Yeah, he needs more power in his shop.

On the positive side, my elctric bill is probably a fraction of his! 

/ubbthreads/images/graemlins/smile.gif


Daniel


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## tvodrd

/ubbthreads/images/graemlins/blush.gif My home "shop" is a toy compared to what I have access to at work! And "work" is very limited as to no wire or conventional EDM, no tool and cutter grinder, no surface grinder, and no CNC! (Turning or milling.) Stone Age! /ubbthreads/images/graemlins/frown.gif

Larry


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## rwolff

[ QUOTE ]

The companion to Dykem is the Dykem remover. It's a spray that cleans off the dye as well as oils and other dirt. A quick spray and the dye just sluices off. 


[/ QUOTE ]

Here's a place you can easily save a few bucks. Since layout dye is a nitrocellulose lacqueur, it can be removed using acetone (cheaper than layout dye remover, and you've probably already got some for another purpose) or nail polish remover (since nail polish is also a nitrocellulose lacqueur - and nail polish remover can frequently be found at dollar stores).


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## gadget_lover

Temporary tool post grinder:


I was cutting the 'cam' off a mag reflector yesterday. That's the long plastic tube on the end of the reflector. After it slipped the second time I found myself wishing I'd finished making that tool post grinder for my lathe.

I threw together a quick mount using zip ties and my parting tool holder. I left the parting blade in place.

It's not accurately trued up, but was sufficient to cleanly trim the part.






Daniel


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## tvodrd

Been there, done that for 20+ years! /ubbthreads/images/graemlins/grin.gif That was a good trick to post! /ubbthreads/images/graemlins/bowdown.gif We have a _real_ tool post grinder at work, but it is such a PITA to set-up/dress, we rarely use it!

Larry


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## gadget_lover

Thanks Larry.

Ant advice on the use of the tool as a tool-post grinder? Is it necessary to align it a particular way? Are hose clamps needed for extra rigidity?

Daniel


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## gadget_lover

The humble mechanic's square. We don't have a post about squares!

May I introduce you to a tool that's become indispensible to me? It's just a hunk of steel with a polished rectangular blade stuck in it. All sides of this tool are ground to exactly 90 degrees. It's porpose in life? It helps ensure that a tool or a part is positioned at exactly the right angle. The blade is in the center of the base, making it possible to align two edges where one goes up and the other down. You'll see what I mean in a second.

This square has a 2 inch blade.








One of the simplest ways to set my lathe's compound to zero degrees is to align the compound to the cross-slide. I already checked that the cross-slide was aligned with the lathe's ways. Note that the blade lays flat on the cross-slide and butts up against the compound. The base is actually hanging over the edge of the cross-slide. Any gap between the blade and the compound indicates the compound is not zeroed.








Once you get the compound to zero, you'll inevitably want the toolpost to be square too. It's just like zeroing the compound. The base of the square hangs off the edge of the plinth and the blade rests on the plinth and against the base of the tool post. The enlargement shows a hairline crack at one end of the blade, indicating that the toolpost is not square to the compound.












Now that the toolpost is square, and the compound is square, you don't need the square anymore, right? There are other uses. When I use my cutoff tool, one of the most important adjustments is making sure the cutter is at 90 degrees to the piece being cut. That is real easy to double check by setting the base against the work and the blade against the cut-off tool. 








This is starting to sound like a Ginzu knife commercial. It slices, it dices, but wait! There's more! There's boring bars! I only have one boring bar holder, so I have to change the boring bar on occasion. It took a while for me to learn that I want the boring bar blade to be just about level. I find the square makes it easier to see when it's level.







There are many other things I use it for. I discovered that it was the secret to making nice consistant bends in strap iron or aluminum using a vise.

A set of shop grade squares is under $20 from Enco or Harbor Freight. HF has a 3 piece set on sale for $3.99 at http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=39047.
You should be able to use the squares to check each other for accuracy if you buy a cheap set.

I keep that 2 inch square in the same box as my lathe tool holders. It's used just about every time I work on something.

Daniel


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## gadget_lover

I was cutting threads on a bezel last night and I discovered some things that I should have known. 

*You don't mess with the controls while cutting threads!*


What makes threading work is the relationship between the position and rotation of the chuck and position and movement of the carriage. For a 28 tpi thread the chuck rotates exactly 28 times for every inch that the carriage moves left or right.

o First, there's the one everyone expects to be a problem. If you disconnect the carriage feed and reconnect it with the threading indicator at the wrong spot it will shift the start of the thread, messing it up.

o But did you know that if you have set up the change gears too loose, one of them might slip a tooth? That changes the critical relationship and causes the carriage to fail to move in exact sync with the chuck's spinning. Your threads become execessively wide or non existant as the tool cuts the tops off.

o I had a brain storm while cutting threads and moved the lever behind the lathe to the off position so the carriage would not move while I was checking the alignment. I re-engaged the gear train when I was done and made the next pass. The thread was not even close to starting at the right spot.

o For reasons unknown to man, I have been known to grab the feed handle for the compound instead of the cross slide when I'm backing it out for another pass. If that compound does not return to exactly the same spot you are screwed!

o Sometimes when you are cutting threads, the tool bites in, grabbing the work. This is a problem mainly when you are cutting threads up to a shoulder. When it bites in, it can actually spin the work within the jaws of the chuck. Just a little, but it's enough to mess up your threads since you lose that critical alignment.

o Believe it of not, the last item on my list is slop in the dovetails of the compound. When you are cutting inside threads, the slop in the dovetails can cause the tool to be pulled below center and then it stops cutting. You keep moving the tool till it does cut, but then it's easy to overshoot.

Hope this helps someone.

Daniel.


----------



## cy

great info!!


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## McGizmo

Daniel,
Sharing these points is one thing but the shear joy of first hand experience should not be underrated!

Hours into a part, what better way to finish if off than to watch it climb up the threadng tool, chip and embed the insert tip solidly into the root of the thread! :thumbsup:

If I shared a short video of how the Hardinge cuts threads and the engagement slide built into the compound, you would probably put a contract out on me! :green:

I paid my dues, honest!!


----------



## PEU

Daniel, don't feel alone  

I guess we all learned the hard way not to mess with controls while threading 

Since I mostly do inch threads in my metric lathe, I only use the single point technique , I only have to look at one thing: how deep the next pass will be, everything else is verbotten


Pablo


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## gadget_lover

I see we've all had similar experiences. I'm glad that I'm not alone. I'd love to see Don's video. I don't think I've seen a Hardinge in use. Grab that camera Don! I promise no contract.

Don's post reminds me of another no-no. The very last thing I do after single point cutting threads is to clean up the lead in area with a light cut so the threads will engage easier. Just the first .025 or so cut even with the bottom of the thread. Sometimes I just put a nice bevel on the edge so it looks nice.

By a show of hands, how many of us have swapped to a regular bit or boring bar, carefully positioned the tool to perfectly cut that few thousandths and then applied power only to realize the feedscrew is still engaged from a few minutes before when you were cutting the threads? You'd think that I'd only make that mistake once. It's agonizing to watch your carefully cut threads disapear under the relentless advance of the boring bar.


I'm glad I do this for fun.

Daniel


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## gadget_lover

I bought a "wiggler" center finder to use with my lathe, mill and drill press. I had hoped that it would increase my accuracy locating the center of holes. 

I found instructions at http://www.littlemachineshop.com/Reference/Wiggler.php but they seemd to have a fatal flaw. They would find edges but you still had to find the center. The instructions would have you find then edge, then move 1/2 the hole diamater minus 1/2 the probe diameter. If the probe was not touching at the proper spot (right on the X or Y axis) you will find yourself out of position when you move the table.


While playing with it I realized that it did a great job of locating the center if you fudged a bit. Here's my technique;

Assume you have a 1 inch hole, and you need to find the center.
Materials: Wiggler with any probe, magnifier ( I use a 10x loupe).

Process:
Mount the probe in the wiggler body and mount the wiggler in the chuck, collet or end mill holder holder. Position it roughly over the hole and lower it till the tip of the probe is just within the hole. 

Now the tricky part. Simply push the probe against the edge of the hole and then turn on the machine as slow as it will go. The probe is lightly held by the body so the probe will be pushed away from the wall when it touches. It will continue to touch one wall of the hole as it spins. This is good. Turn it off and examine the results.

Rotate it one turn by hand and use the x-y handwheels to move the probe closer to the wall that is furthest from the arc of the probe, visually centering the rotating probe. I usually move it 1/2 of the distance between the probe and the wall. When it looks good, push the probe out again till it touches a wall. Again, it will be pushed toward the center by one or more walls as it spins, but less this time. 

Repeat this until until it looks like the probe stays in contact with the wall for the full rotation. This should be pretty close. Use the magnifier to make sure. 

Lock the table and replace the wiggler with your cutting tool. It should be perfectly centered.

Here's a wiggler in my drill press. As you can see, it does not touch the left wall but does touch the right wall. I need to move the piece to the right to get closer to the center.







With a few minutes practice it becomes a quick and easy task, taking less than a minute to get it within a thousandth or two.

Daniel


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## 6010

i think i need a bigger lathe !http://www.wymoreinc.com/images/600_P5220012.JPG


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## Rothrandir

maybe get a test indicator gadget?

noga also makes a really nice arm that chucks up into the mill spindle, and can accept either a test or dial indicator at the end. it's similar to their magbases, which i *highly* recommend.


----------



## gadget_lover

Rothrandir said:


> maybe get a test indicator gadget?
> 
> noga also makes a really nice arm that chucks up into the mill spindle, and can accept either a test or dial indicator at the end. it's similar to their magbases, which i *highly* recommend.



OK, I'll bite. How do you use the test indicator to locate the center of holes? I've tried using one on an arm that's in the chuck, but that assumes that I have the X or Y axis located properly and that the arm is on the same axis as the indicator's probe. That did not work

If I use the indicator as the probe with the same process as I outlined above... Yes, that will work, right?

It looks like the cat's meow is a coaxial indicator. 
Taken from :  http://www.haascnc.com/solutions_tooling.asp



> TIP: A huge time saver for finding the center of a hole or round part feature is a coaxial indicator. This indicator fits into a collet chuck, and you use it while the spindle is turning. Manufacturers claim that you can use these indicators at speeds up to 800 rpm, but the 50 to 100 rpm range works well; if the spindle is rotating too fast, it is difficult to tell which axis needs to be adjusted. A restraining arm allows the face of the indicator to remain stationary while the spindle rotates. With each rotation of the spindle, the indicator dial will show the amount it is off-center. You simply jog the machine axes while watching the indicator movement. This saves time because you can start the rotation while the indicator is off-center by as much as 0.250 inch, and you can literally dial it in within seconds.




Daniel


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## Rothrandir

the coax is nice, though honestly i don't know much about them, never having used one myself.

a test indicator can be used in the same way you would dial a bar in a lathe chuck, but kind of the opposite...pretty much exactly like what you're doing, except the dial indicator has a dial to look at, where the wiggler does not. a little mirror might be handy also for seeing the dial when it's behind you.
the thing is, you will probably need to have it on a magbase type arm, so that you can position it for larger holes.


----------



## PEU

AHHHHHH  

So thats why my indicator with magnetic base came with lots of tips, from day one I only used one...

Will have to try now 


Pablo


----------



## tvodrd

Accurately locating _existing_ holes to a spindle really calls for a test indicator. For the mill, it goes in the mill's spindle. For the lathe, a magnetic base is the ticket. Dan's Little machineshop link to its usage is fairly correct. What the failed to mention is that when working to layout, normal practice is to center ponch hole locations. You scribe lines, grab your automatic center punch, and try your best to nail the lines' intersection. :green: (Yes, there are some optically-aided center punches that improve your odds.  ) The wiggler really comes in handy aligning a mill's spindle to the center punch mark. With the wiggler in the machine's spindle, use a pencil or something to get it running true with the spindle. Next, X-Y the workpiece so that you can use the quill to run the wiggler into the prick pinch mark. When you back it out, if it is still running true, you are located. 

Larry


----------



## gadget_lover

tvodrd said:


> The wiggler really comes in handy aligning a mill's spindle to the center punch mark. With the wiggler in the machine's spindle, use a pencil or something to get it running true with the spindle. Next, X-Y the workpiece so that you can use the quill to run the wiggler into the prick pinch mark. When you back it out, if it is still running true, you are located.
> 
> Larry




That makes good sense. Thanks for the tip. I would not have thought of the centerpunch depression moving the probe off center if the mill's spindle is not right over the center of the mark.


For quick and dirty locating, simply using the probe and magnifier as described above seems to put you within a thousandth or so when you can see the probe touching on all sides of the hole as the spindle is turned 360 degrees. I'll check that later today using a dial test indicator and update my post.

EDIT: Yup. I checked my work using the DTI and I was just about .001 off using just the plain wiggler probe. It was hard getting the DTI just right since the DTI showed the hole was not totally concentric.


Daniel


----------



## cmacclel

Great post guys.... Is there a nice step by step how to out there to cut threads for a newbie?? I just picked up one of these off of Ebay locally for $500. For the price I just couldn't pass it up.

http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=44142


Mac


----------



## gadget_lover

cmacclel said:


> Great post guys.... Is there a nice step by step how to out there to cut threads for a newbie?? I just picked up one of these off of Ebay locally for $500. For the price I just couldn't pass it up.
> 
> http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=44142
> 
> 
> Mac



Local! $500! 17x31 ! ERk!






Ok, there is a thread (or two) on threading. You can start with http://candlepowerforums.com/vb/showthread.php?t=49164 (How do I make threads?)


You really have too much machine for a beginner. Please send it to me (pre-paid freight) and I'll send you a HF 7x10 (also pre-paid freight to be fair) to learn on. 

Seriously, Congrats on finding such a good deal. I hope it works well for you.

Daniel


----------



## cmacclel

Ha ha funny. I really wanted this machine

http://www.grizzly.com/products/item.cfm?itemnumber=g0516


But for the price the one I got can't be beat. It still had the packing grease on it. The only thing that concerned me was the switch was rewired. As soon as I switch the Emergency stop button on the green armed light illuminates on the control panel. Then all I have to do is move the switch to either forward or reverse and the machine starts up. There no need for me to push the green button to start.


Mac


----------



## gadget_lover

*Playing with wood*



I bought my lathe (HF 7x10) to make flashlights, and I've ended up making all sorts of things with it. I've made parts of plastic, aluminum, brass, steel and now.... wood.

The 7x10 is not a big machine, but it's prefectly adequate for small wood projects. I've turned ballpoint and fountain pens, and I've made a plumb-bob shown in the bragging thread. The major functional difference between a metal lathe and a wood lathe is the presence of a tool rest instead of a toolpost.

If you've never seen a wood lathe, it's similar to a metal lathe. It has a headstock and a tailstock. It has a moveable crossslide (sorta) upon which to steady your hand held carving tools. The wood is often held between centers, though there are chucks and backplates used too.

The wood is carved while it's spinning by holding specially shaped chisel against the wood. You support the chisel against a metal rest that is placed within 1/4 inch of the wood. You can buy mini lathe turning tools at woodcraft for $39, though I got mine on sale for $20. http://www.woodcraft.com/family.aspx?DeptID=4038&FamilyID=4434

Here's the simple tool rest that I made for mine. I simply took a 1 inch by 1 inch by 6 inch angle and drilled a hole in it. Then I lowered the edge that the tool rests on to about 5/8 inch. You want it close to the centerline of the spinning wood.

I should have used steel or iron, but I had 6 foot of aluminum at hand, so that's what I used. The problem with aluminum is that the sharp edges on the shafts of the tools sometimes dig into the softer aluminum. This is the tool rest by itself..








It's bolted to the toolpost plinth (that raised area under the toolpost) by a 10mm bolt. You can rotate it to keep it parallell to tapers. Here it is with a tool in hand.







Now, to bring it back to flashlights......

The process for turning small hollow parts (like fountain pens) can apply to flashlights. The trick is to mount the block of wood on a reinforcing tube before turning it. For pens you use a small brass tube and glue it to the wood. Then you mount the reinforced wood on a mandril (a long, tight fitting rod) and mount that in the lathe's chuck. You can turn hardwood down to a very thin veneer a few 1/64s thick.

If you wanted a wood sleeve on your flashlight, you would drill a block of wood to the same size as your flashlight tube. Just like a pen, you'd glue the wood in place and then mount the flashlight in the lathe. You can use normal (sharp) metal cutting bits in the toolpost if you want a straight, flat curve. You can use a tool rest and hand held tools if you want graceful curves.


Here are some things made this way. The pen was made using standard metal turning lathe bits and the stock toolpost. The plumb-bob was made using the toolrest and hand held turning tools. Both were drilled and have a 7mm brass tube down the center. Both were mounted on a mandril for turning.










A few cautions about wood. Wood is messy. If you start with a 2x3 inch block and turn it down to a 1x3 inch curved wine bottlle stopper you will have about around 1/2 cubic foot of sawdust. It will go everywhere, including your eyes and nose. A shopvac will help a lot, but eye protection is really needed. And don't forget to empty your pockets when youare done. You'll be surprised by the amount of wood chips in your shirt pocket.


----------



## ABTOMAT

gadget_lover said:


> Local! $500! 17x31 ! ERk!
> 
> 
> 
> 
> ....
> You really have too much machine for a beginner. Please send it to me (pre-paid freight) and I'll send you a HF 7x10 (also pre-paid freight to be fair) to learn on.
> ...



I'd say actually doing anything on it close to 17x31 would require divine intervention. Probably would be a good 9" lathe looking at the design. Most folks learn to hate these things after a few years, but for $500 you certainly can't complain. Great deal.

In the "woodturning is messy" vein, make sure you cover your lathe while woodturning and clean it meticulously afterwards. That dust gets packed into all the working parts. Not much to go wrong with a tiny machine like a 7x12, but ones more complex can have problems.


----------



## cmacclel

How do you cut threads on your lathe??

Do you 

1)Set the compound up for 29.5 degrees

2)Align the 60 degree cutter so that it is Parallel to your work using the 60degree fixture.

3)Touch the 60 degree cutter to the part your threading then zero out both dials

4)Back off the compound slide a full turn

5)Turn the cross feed handle in to the depth of threads your cutting Example..... 20tpi is .0635

6)Turn the lathe on then turn the compound slide *only* in multiple passes until you reach zero again??



This is how I was taught from 2, 20 year machinests. Everytime I cut threads this way they do work but the threads are not square....there more sawtooth like. I found if I don't use the compound slide and just use the cross feed my threads look great.



Mac


----------



## 6010

Sounds ok but you need to take like .005 or .010 passes not all at once if that is what you are doing . -A


----------



## cmacclel

6010 said:


> Sounds ok but you need to take like .005 or .010 passes not all at once if that is what you are doing . -A




I usually take around 0.005 passes

Mac


----------



## yclo

Taig Lathe unassembled kit:






And a L4 thrown in for size:





And here's the silly newbie trick, so I got one of those cheap drill presses that is made in China since that's a cheap source for a motor I could use with the Taig.

The Taig pulley has an 1/2" (12.7mm), and turns out the motor has a shaft diameter of 14mm.  And without the motor/pulley setup, I can't even bore the pulley out! Lucky the guy I bought it off is willing to bore out the pulley for me.

-YC


----------



## tvodrd

Hi Mac,

I learned threading from a college textbook someone gave me years ago. The 29.5deg compound setting results in only cutting the forward side of the 60deg groove on each pass (for external threads) and allows heavier cuts. Set your cross slide about .005" short of zero. Make multiple passes using the compound until you reach zero. Then make one final pass at full zero on the cross slide. The cutter will cut both sides of the groove to correct V-form. It works for me. 

Larry



cmacclel said:


> How do you cut threads on your lathe??
> 
> Do you
> 
> 1)Set the compound up for 29.5 degrees
> 
> 2)Align the 60 degree cutter so that it is Parallel to your work using the 60degree fixture.
> 
> 3)Touch the 60 degree cutter to the part your threading then zero out both dials
> 
> 4)Back off the compound slide a full turn
> 
> 5)Turn the cross feed handle in to the depth of threads your cutting Example..... 20tpi is .0635
> 
> 6)Turn the lathe on then turn the compound slide *only* in multiple passes until you reach zero again??
> 
> 
> 
> This is how I was taught from 2, 20 year machinests. Everytime I cut threads this way they do work but the threads are not square....there more sawtooth like. I found if I don't use the compound slide and just use the cross feed my threads look great.
> 
> 
> 
> Mac


----------



## TranquillityBase

gadget_lover said:


> Today's learning.... When I use a parting tool (I use the 1/16 inch bar) it tends to leave a nice smooth finish on one side and a nub on the other. It seems inevitable that the nub will be on the workpiece that I've just finished, not on the other side. This is a shame seeing that the tooling swirls look pretty good by themselves.
> 
> I now have a left hand and right hand parting tool. I put just a few degrees of slant on the cutting edge (with a stone) so that one side cuts just a thousandth or so deeper than the other. When I part the piece I can predict which side the nub will be on.
> 
> Let me know if that was not clear and I'll elaborate.
> 
> Daniel


*


----------



## gadget_lover

That's a cute little lathe, Yclo. I'd read about the small Taig models but had never seen one. Did that drill press motor work out OK? Have you made chips with it yet?

What was your reasoning behind buying that model? It certainly looks intrigueing with all those T-slots on everything.

My key cutting machine is about the same size. They use, believe it or not, a sewing machine motor to turn the cutting wheel.



Thanks for the tip on the cut off tool, TB. That's similar to what I've been doing.


Now for the obligatory silly newbie trick.

I put a stray piece of scrap in my micro mill's vice, and wanted to make two small holes 1/2 inch apart that were pretty well centered on the piece from left to right. Normally you find the right edge of the piece, subtract the radius of the center finder from the width of the piece and crank the table to the left 1/2 of that figure.

What I did instead (since precision was not of the essence) was to put the wiggler in the chuck, and rotate it so it's probe hit the vice jaws on both sides. That leaves the tip of teh probe pushed in to the smaller of the two distances. I moved the table a few times till the wiggler hit both sides as it rotated. It was now close enough for gov't work. I chucked up the drill bit and drilled away. It worked like a charm! The holes were perfectly centered just like I wanted. No math, no over or under cranking. Pictures available on request 

Daniel


----------



## TranquillityBase

I had a brain fart...must not have read all of your post. 

TB


----------



## gadget_lover

I'm not sure if this next tip is really valid or not. I just read about it on another list.

The general idea is to sllow you to work on two pieces at once without having two lathes. The solution? Use a second chuck. OK, not two at once but two pieces without losing the alignment in the chuck.


The situation that was mentioned was one where you were making parts that mate. While working on the second part you realized you needed to do one more step ( cut a bevel on a ring, for instance ) on the first part.

You can save your current alignment if you remove the chuck with the piece still in it and put your other chuck on the spindle. Then you can alter the first peice, test fitting as required and you can put the original chuck back in the same mounting holes when you are done.


Daniel


----------



## Anglepoise

Threading tip.

I just got caught again.
Went to set my compound slide to 29.5 degrees
and yes....I made that same mistake again.

While the compound degree scale reads 29.5 degrees, the actual infeed angle is 60.5 degrees.
So remember to get this right. In my case with my lathe, I always need to set the compound to read .....60.5 degrees, not 29.5.

I think that might have been Mac's problem ^^^^^.


----------



## gadget_lover

David, can you post a picture of that? I'm always getting my angles backwards. My lathe's scale reads 0 when it's perpendicular to the ways, and goes up on both sides to 45 (ish) degrees.

Daniel


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## gadget_lover

Some of us with small shops have a problem with space. I have had my lathe setup on a glorified sawhorse between the clothes washer and the path to the door. While this has worked well in general, it's had a few problems. When I first turned a large piece of iron and used too much speed and too much cutting oil the resulting 'racing stripe' of oil and iron dust across the washer almost caused a domestic crisis.

When I set up my new lathe, I actually set it on the workbench. The only problem, as you might note in the picture below, is that I'm a pack rat and use the shelves behind the lathe. I was not looking forward to relocating the toys or losing the storage space. The idea of metal chips getting into the variable power supply was downright scary.







So I thought to myself "Self? What can you do to put doors across that space?" I racked my brain but could not create a way to do that and still have access to the space between the lathe and the shelf. The project was further hampered by a 10x6 storage ledge suspended from the rafters. The ledge is almost as low as the storage shelfs.

So I came up with this solution. It contains the chips, protects the equipment behind the lathe and is easily removable. 






I'll let you know how well it works with time.

Oh? did I forget the newbie trick? The white sheet is a window shade. It's suspended about 3 inches in front of the shelf. I had to mount it on a 1x3 board which is then screwed to the bottom of the ledge. If I were doing it again I'd use a stiffer board. This one is really too flimsy and flexes as I pull down the shade. I could just glue/nail/screw a 2x1 to the side of it to give it some vertical rigidity.






Daniel


----------



## Anglepoise

gadget_lover said:


> David, can you post a picture of that? I'm always getting my angles backwards. My lathe's scale reads 0 when it's perpendicular to the ways, and goes up on both sides to 45 (ish) degrees.
> 
> Daniel



Sorry I took so long to get a pic. The brown arrow points to a white dot at 29.5
degrees. If I set the compound to this setting and attempt to cut a thread, I will be in trouble as the angle to the thread will be 60.5.

So I use the black dot, depicted with the red arrow, that gives me 29.5.

Best of the season


----------



## gadget_lover

David, I'm not sure why you are doing it that way. It seems like too sharp an angle.

Looking at my lathe, the 29.5 indicated on the protractor matches the 29.5 indicated on yours. You can see that in the first picture.








I use a 60 degree tool with a carbide insert aligned so the shaft is at a right angle to the chuck centerline. The 60 degree insert is then perfectly aligned. This makes the thread profile exactly 60 degrees. 








In this next picture, you will note that the leading edge of the tool is the left one. It's perpendicular (less 1/2 of a degree) to the movement of the compound. If the compound is advanced the left side of the tip will do the cutting.








If I set teh compund to a more accute angle of 60.5 degrees, the sides of the insert will no longer be perpendicular to the motion of the compound. The left and right sides of a 60degree insert would be cutting. What am I mis-understanding?

BTW, forgive the color in these pictures. I did not bother to set the white balance and my new camera is sensitive enough to use the available light from a 60 watt bulb. I'll have to remember that!

Daniel


----------



## Anglepoise

Math is not my strong suit. However although our angle graduations are slightly different, both compounds are set over at 29.5 degrees ( yours and mine photo above.)

Now if we were to do some threading with the compounds as shown, and the infeed was from said compounds, then the thread produced would be unusable as instead of the infeed matching the flank of the cutting tool it would be way out at 60.5 degrees.

I can not explain it better as I lack the math knowledge.

The right hand side of your cabide insert mus be parallel to the compound body. Its claerly not in your pic. See pic below. The surfaces with the red arrows must be parallel so that the infeed matches the flank of the tool.
Trust me on this one.


----------



## gadget_lover

Anglepoise said:


> The surfaces with the red arrows must be parallel so that the infeed matches the flank of the tool.
> Trust me on this one.



Trust I have. Understanding I do not. 

Really, I'm just trying to understand the whys and wherefor's. 


After thinking about it a bit, I think the problem is that we are talking about two different angles. I always thought that the compound was to be set to 29.5. It seems that it's the infeed angle that needs to be set to that. The web page http://www.mmsonline.com/articles/010302.html specifies infeed angle.

Is this picture correct?






Daniel


----------



## Anglepoise

gadget_lover said:


> Is this picture correct?
> 
> Daniel






You are correct that the compound has to be set at 29.5 degrees.
The problem is that the degree scale on both our machines are not measuring the correct angle.
The 29.5 degrees must be the infeed angle in your latest picture.( shown at 60.5 in your pic )
Set that angle ( infeed angle )to 29.5 and you will have it correct.


This fools so many people, and caught me again last week.
If you get it wrong and you infeed with the compound, you get a sort of 'butress' looking thread that is all wrong .


----------



## tvodrd

Daniel, your set-up is "textbook." The "29.5deg" is measured from the spindle centerline. Everybody remember the very final-to-size cut should be made with the cross slide rather than compound so the cutter just cleans up the trailing side of the V, leaving a perfect 60deg form. Just using the compound will result in a 60.5deg, slightly asymetric V. Just using the cross slide usually kicks up a ugly burr at the crest of the thread and is harder on the 60deg cutter's point.

(I have edited this post twice for clarity.)

Larry


----------



## Anglepoise

This is the way I set it up.
Compound side parallel to flank of tool.
Great article about 'Infeed' options and angles
"Infeed angles and options"


----------



## tvodrd

David, you have me going back to the "books." I rarely single-point any more- just for larger parts, but my "recollection" is 29deg from spindle centerline. The 60deg tool should only cut on the leading edge (unless doing really coarse threads) and your final cut to full V is with the cross slide. Of that, I am certain! :shrug:

Larry


----------



## Rothrandir

most of my threading experience is on cnc lathes (lots easier  ), but i've always done it the same as in daniels pictures.

you're cutting with the left side of the tool, and the reason you set the compound is so that you can engage the front of the cut instead of the full cut. i believe 29.5 is used because it is just less than 30, which is half of the thread profile. with 29.5 you will push the tool into the thread on just about exactly one side.
i would guess that with a more direct cutting angle, you would be cutting with both sides of the tool?


----------



## CNC Dan

Anglepoise has it right in his pic.
Daniel has it wrong in his pic.

You wan't the direction of feed to be near parellel to the "non cutting" edge of the tool.


----------



## cmacclel

My Machine set to 29.5 Degrees looks like Daniels. I have been doing threads without the compound angle just using the Crossfeed and am getting good results. Maybe because my compound angle looks like Daniels when set to 29.5 Degrees was my problem? Hmm I need to keep an Eye on this Thread 


Mac


----------



## Rothrandir

screw the math, lets try to figure out exactly why we want the compound set at any angle.

just using the crosslide, and feeding straight in, you should cut equaly with both sides of the tool. resulting in a good thread profile, but more cutting forces.

setting the crosslide as in danels picture, you will engage the thread, with all of the cut on the front of the insert.

setting the crosslide as in angels picture, it would seem that you will still engage the cut with only the front side, as it is set to push in at only a slight amount less than the trailing edge of the thread.

after further consideration, it would seem like angels should work best. the thread being 60degrees can cause a bit of confusion when trying to visualize tool engagement. threads have a 60degree form, not 45 so that must be taken into consideration when you visualize the toolpath.
if you feed in at 29.5 from the centerline, you should engage the face of the cutting tool head on, but it would seem that there is the possibility to feed through the trailing edge of the thread. as an example, draw a big (several inches at least, so you can easily see what is going on) ~60degree /\ shape on a piece of paper (or if you're like me, straight on the desk). now take the pencil, and point it through the front of your /\ so that the pencil is lined up to go straight through the front of the /
doing so, it appears that upon multiple passes, the tool will not only engage the face of the thread, but that it will *not* follow the correct profile.
now rest your pencil next to the \ side, so that you're paralell with it, (slightly less actually, but only by .5degrees). it should look about like this \\
it would seem that this movement would follow the thread form more accurately, and result in a cutting action still on the face of the tool, yet still follow the thread degree.

my guess is that when the tool is set at the less agressive angle, it has the potential to cause a sawtooth pattern, because it is not riding the 60degree profile, it is creating a slightly new z location at every engagement.

upon further recollection (i've actually only singlepointed on my manual several times, being lazy and having die's for most size i've had to use) i think i set the crosslide, but after having problems with it, i would simply use the compound to bring the tool in.

i'm no math expert, and i must admit that i never really took the time to understand exactly why you wanted to set the crosslide. i undestood the princple, but never fully understood what was happening. after thinking it out, i'm going to have to agree with angel, and say that by following the trailing edge of the thread, you should be able to follow the 60degree profile, while still engaging the cutting face of the insert.
using the less agressive angle appers to contradict the 60degree thread profile more with each additional pass.

actually, it's very simple now. threads are 60degrees total, 30degrees each side from the center, straight down (front to back). therefore, your crosslide should be the same. if you were to imagine having another crosslide, set up mirrored to your existing crosslide, and meeting at the tip, which angle will result in a shape that looks like a proper thread?
if the angle of the thread is measured from front to back (30per side), shouldn't you set your crosslide along the same axis? straight out from the thread, instead of through the spindle centerline?

if you look at:





picture from the link angel referenced, you can see on the pictures a little arrow showing the tool engagement direction. that arrow could be thought to represent your crosslide.

i just drew this up real quick. it's dirty, but should give an *idea* of what's going on.


----------



## cmacclel

Thanks for the Pictures guy's  Now that i can see the problem quite clearly. My compound slide angle is marked differently like Daniels. In order to cut at 29.5 Degrees we must set the compound slide to 60.5 degrees. Thats where the pictures really helped me. Your compound slide should be paralell with the right edge of the 60 degree cutter. 



Mac


----------



## McGizmo

Roth,
Don't you mean the arrow represents the compound and not the cross slide? I use the 29.5 deg method shown in the illustration most of the time. In a few cases of internal threads, I have used the cross slide for 0 degree in feed. This was when I wanted to cut the thread as close to the bottom of the bore as possible. The compound slide on my Hardinge has a quick lever feed in addition to the leadscrew adjustment so I can engage and disengage the cuting tool without any adjustment to either the compound or cross slide leads. I really do feel like I am cheating these days!!  With the Hardinge, you can set stops on both the start and stop "Z" positions of the thread.


----------



## Rothrandir

yes don, sorry about that.
i think the crosslide was mentioned in a few previous posts, so i said that instead of compound. 

most of the time i'm *using* my tools, not trying to remember which part is called what :nana:


----------



## gadget_lover

I think it's pretty clear why I was having such problems with using the compound to cut the threads. I had experienced the saw toothed thread too, and thought something had slipped in the gear train. In reality, I'd given it too much infeed.

Here's what I finally understand (just in case anyone else is still foggy about it )


----------



## gadget_lover

Well, I'm convinced. I've been doing it bass ackwards. I needed to think about all of it for quite a while. Using 29.5 degree COMPOUND angle seemed to work OK because the last few thousandths are removed by using the cross-slide to go straight in. That should clean up the jaggies on the right. using a 29.5 INFEED, on the other hand, leaves the sides pretty darn smooth in the first place.

So I moved my compound to 60.5 and realized that OOPS, the protractor does not go that high. It only goes to 45. To make up for this, I made a second index 30 degrees to the left of the original. Now I can rotate the compound till the new index lines up with 30.5 and It's all ready to go.

First, adding teh new mark.






Second, using the new mark. Notice the nice clean cuts in my test piece.






Darn, now I have to go back to my earlier posts and correct them.

Daniel


----------



## gadget_lover

I have several of those digital Calipers. Some have been modified for special circumstances, so they are used very little. A couple are just too large to use for everyday use, so they sit there on the hook or in the box till they are needed. All in all, I think I have 6 of them.

I bought many of them on sale at the same time so of course I put batteries in them at the same time. Would you believe that all of a sudden the batteries died within a month of each other? These units are actually "on" all the time, slowly drining their little batteries. I swapped in new batteries (bought on sale on e-bay) as I discovered they were dead and put the calipers back on their hooks till they were needed again. Fast forward to last month, when I repeated the process again.

After replacing all the batteries, I decided to remove the batteries from all but the two that I use frequently. I put the spares in a plastic baggie hanging on a pegboard hook. That's worked pretty well so far.

Today as I was removing the battery I realized there was a stupid newbie trick I could use here.

The battery uses the case as one electrode, and an isolated area on one end as the other electrode. The battery holder has a little recess that cradles the battery, with a contact on the very bottom. If the battery is inserted properly both contacts touch the right places to conduct electricity.

As you can see from the picture, there is no metal touching the batttery terminal when it's inserted backwards. That's the trick. You can store the battery IN the caliper so it does not get lost and the battery does not run down. 







Daniel


----------



## gadget_lover

Can you figure out what this is without scrolling down????











Don't peek yet....

.

.

.

.
It's a carriage stop that clamps to the V way on your lathe. You use it when you want to move the carriage back to exactly the same point time after time. For instance when turning to a shoulder. The screw on the right turns in and out to provide a fine adjustment.









But what's the newbie trick? I realized that the V way of the lathe is actually a 90 degree angle tilted to 45 degrees and with the crest milled off. That makes milling an accessory to fit the groove almost simple. Just tilt the piece you are milling to 45 derees when milling the groove. The mill diameter does not even have to be an exact match for the width of the V, since the cut can overhang a bit. My ways appeard to be 11 MM (.433 inch) and I used a single pass of a 7/16 end mill. I could have used two passes with a smaller mill.






I want to make an adjustable limit switch, and possibly an improved tail stock, so I was happy to find that I can mill that groove.

Daniel


----------



## gadget_lover

SIlly Newbie trick of the day.

My wife wanted something to set her omochi grill on to suspend it about 1 inch above our electric stove's burner. Omochi is a Japanese rice cake that is toasted before eating. She likes it, I don't care for it.

The grill is s simple round steel mesh with a 3/8 inch wide pressed sheetmetal ring around it. So I made 3 really neat little legs out of 6061 aluminum. They stand 1.25 inch tall, 2 inch long and 1/2 inch wide. I milled a groove to recieve the ring around the grill. I also added a clearance ring so that each leg will sit right up against the burner's chrome drip tray. When in place they are almost locked together.

I made all three pieces identical in every dimension. Sitting side by side they looked like one piece of metal. I was quite pleased with my little project.

Now for the really, really stupid trick. I decided that I would "seal" the aluminum by boiling it for 20 minutes. I'd read some where that you soak them in 210 degree water for 20 minutes to seal the aluminum's pores. It sounded like a good idea for a product that would be used around food.

So I plunked all three pieces in a teflon coated sauce pan witha quart of fresh tap water and set it to boil while I cleaned up my shop. I checked it at 10 minutes and noticed a light brownish grey coating. Cool. Something was happening. I turned down the heat toa low boil and forgot about them for another 30 or 40 minutes.

I was blown away to see that the aluminum was a very striking dark brown, almost black. It looked very cool. I started cooling the pan by adding cold water and within a minute I was able to pick them up in my bare hand.

That's when I realized that the uniform dark coating was only on the exposed surfaces. The side that was down against the bottom of the pan was a mottled light grey with dark blotches around the outside edges. The bubbles under the pieces had kept the water away from the metal.

So there's a right way to do this , but my way was not it. I finished off the "finish" by using a "Marks a lot" permanent marker. It seems quite permanent.

So if you want to "seal" the aluminum you should first search for for directions and then follow them. I did not use distilled water, I did use a teflon coated pan and I probably had the heat too high for too long. If it were a flashlight I would have cried.

This is the interesting finish from just the boiling. It's much darker in real life, the flash bleached it a bit.





Daniel


----------



## cmacclel

*My contribution*

Here's my Huge $$$ Indexing head  Also my Big $$ DRO is pictured too! Oh don't mind the cheasy mill in the drill chuck trick  With a collet in, my quill doesn't go down enough 












After Clean up







Mac


----------



## gadget_lover

*Re: My contribution*

That's some pretty nice machining there, Mac.

The indexer is inovative. For that type of work it's probably just as accurate as it needs to be. Do you have to loosen the vise each time you rotate?

Daniel


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## cmacclel

Yes you have to loosen the vise each rotation. I was going every 30 Degree's in the picture.

Mac


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## gadget_lover

Very cool. I did the grooves on the carriage stop's knob (post 169) by running a small end mill across it very 20 degrees. I used a rotary table. Even so, on one of the cuts I missed by 10 degrees. Just goes to show you that expensive accessories don't insure perfect results.

Daniel


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## praetor coda

Hey angelpoise I've been reviewing you pages, nice. may I ask where did you get that nifty looking QCTP on your lathe? Can I get a hold of one for my machine


----------



## cmacclel

gadget_lover said:


> Very cool. I did the grooves on the carriage stop's knob (post 169) by running a small end mill across it very 20 degrees. I used a rotary table. Even so, on one of the cuts I missed by 10 degrees. Just goes to show you that expensive accessories don't insure perfect results.
> 
> Daniel




I'm looking at purchasing this one.

http://www.use-enco.com/CGI/INSRIT?PMAKA=200-1143&PMPXNO=953089&PARTPG=INLMK3


Mac


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## gadget_lover

Ok, Today's silly newbie trick.


I use a Craftsman brand 2 gallon shopvac to suck up the swarf from my milling, turning and wood cutting. It has a lot of suction and is a good size for lugging around to the part of the garage where it's needed. It really will hold two gallons of swarf. I know because I've filled it before. 

The problem with this (and probably all small vacuums) is the ease with which the hose clogs. The hose is corregated to make it flexible. An errant piece of wire, a long piece of swarf or a curl of wood and the hose becomes clogged. The hose is 5 foot long, so I have to cram a 5 foot wooden dowel through the clog to clear it. It's also an opaque black so you can't quite see the clog.

See all the nice ridges where anything at all can wedge itself? See the reduction from 1.5 inch to 1.25? Isn't that great engineering?






CAUTION: Do NOT hold it above your head while peering in one end, hoping to see the over head light through the hose. Twice.

OK, now for the trick.

The hose is 1.25 inch OD where it plugs into the vacuum. Nothing special. The other end is also 1.25 inch. I found clear vinyl hose at Orchard supply that is 1.25 OD and 1.0 ID for less than $1 a foot. I bought 8 foot of it and brought ot home. It fits the craftsman like it was made for it. The tools fit on the other end too. It's not real flexible, but that's OK because it keeps it from collapsing. It's actually just as flexible as the original.

The original hose is sitting there for comparison.





I've been using this for a hose for over a year. I don't recall ever having a clog in the hose even though I regularly vacuum up long, stringy aluminum curls. I suck down the oily aluminum chips from my mill and they don't get stuck either. There is stuff that won't go into the hose, but that's OK since the vacuum's inlet is only 1 inch in diameter anyway.

This hose and vacuum combination clogs less than than my big shopvac with it's 2.5 inch hose. As a mater of fact, I have not used my big one much this year. I have wondered if a smooth wall equivilent is available for the big guy.

Daniel


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## gadget_lover

cmacclel said:


> I'm looking at purchasing this one.
> 
> http://www.use-enco.com/CGI/INSRIT?PMAKA=200-1143&PMPXNO=953089&PARTPG=INLMK3
> 
> 
> Mac



That sure looks like a nice one. 3 inch tall with an MT3 taper should be very versatile. I wish I had that much room. An 8 inch table would overhang my mill's table by several inches! 

I bought the 4 inch version from Harbor Freight. It's not a bad choice, but I wish I'd understood the reason for the taper in the middle. The HF has, essentially, just a hole in the middle. It's OK for me since I neeeded low and small for my micro mill. Adding a 4 inch high table and a 2-3 inch chuck would have taken up most of the table to quill space.

Daniel


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## cmacclel

gadget_lover said:


> but I wish I'd understood the reason for the taper in the middle. The HF has, essentially, just a hole in the middle.
> 
> Daniel



Please enlighten me  


Mac


----------



## gadget_lover

OK, I'll try.... 

As I understand it, the MT3 taper of that table will allow you to mount things precicely in the middle of the table. A drill chuck mounted on an MT3 taper, for instance, will allow you to grip small round parts securely and have them exactly centered. 

With a dead center in that taper and a matching tailstock you can actually support an odd shaped piece between centers. The tip of the dead center can also be used to center the table under the mill's quill.

Finally, having a perfectly round taper helps when using a centerfinder or wiggler to perfectly center the table under the mill's quill.


The hole in my 4 inch rotary table is about 1/2 inch with a 60 degree taper for about 1/2 inch, then a 5/16 x 18 threaded hole. I made the following insert in an attempt to allow me to center a part. The brass tip is spring loaded. The idea is to centerpunch a dimple in the part to be mounted, then locate that dimple with the brass point and secure it with normal clamps.










I also made a mount for a two inch chuck that has a 1/2 inch threaded mounting hole. This allows me to grip things in a way that allows me to mill the top surface. I need to make a better mount that supports the whole base of this little chuck, not just the center. I don't think I have the angles right on this adapter either.







Did that help? Did I miss anything?

Daniel


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## Anglepoise

praetor coda said:


> Hey angelpoise I've been reviewing you pages, nice. may I ask where did you get that nifty looking QCTP on your lathe? Can I get a hold of one for my machine




The QCTP is made by Multifix Suisse but was purchased new back in 1984. At that time there were few alternatives to buy if you wanted a QCTP and this set up was very expensive.

The only link I have is below
Multifix Suisse


----------



## gadget_lover

That is a seriously beautiful work of art, Anglepoise. It probably cost more than my lathe.



Today's silly newbie trick...

I was milling a slot in the side of a tube a few months ago and realized after I was done that while I'd hit my mark, I did not have the tube oriented properly. The mark was just off to the side a few degrees and that ruined the alignment when I put everything together. The quandry was how to ensure the mark was at the top of the piece when I put it in the vise, given my poor spatial reconning skills.

The problem came back last week when I was milling slots in the side of a knob. The knob was mounted on my rotary table, but the whole time I worked on it I was feeling that it was not quite centered.

The solution came to me today as I was cleaning my work bench. The dial indicator has a small nub on the top where the plunger rod comes through. The retaining knob on top of teh plunger is just marginally smaller than the nub. HMMMMM.







Yes, there was enough nub to grasp in the jaws of my mill's chuck. I hand tightened the chuck and spun it to verify that it was centered. Then I popped an aluminum cylinder in the vise and lowered the mill spindle till it just touched. Moving the table back and forth, I stopped at the point where the DI needle stoped moving. That was top dead center!





As you can see, my best guess at positioning the mark at the top of the piece was off by a little. You can see the indicator point is to the left of the mark. I repositioned the cylinder and got it spot on by the third try.









This will also work with drill presses.

I see I've been hogging this forum. I'll let others post for a while.

Daniel


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## wquiles

That is indeed a very cool tip - thanks!

Will


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## praetor coda

Thanks Angelpoise, to put it bluntly, it is said that if you have to ask how much something cost, then you can't afford it, I only asked where would you get one.:thanks: 





Anglepoise said:


> The QCTP is made by Multifix Suisse but was purchased new back in 1984. At that time there were few alternatives to buy if you wanted a QCTP and this set up was very expensive.
> 
> The only link I have is below
> Multifix Suisse


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## Anglepoise

praetor coda.

I purchased mine from a company in Vancouver, Canada.
I talked to a salesman today and they still have the full line of Multifix Suisse in stock.
Good honest company.

Thomas Skinner Machine tools


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## wquiles

Anglepoise said:


> The only link I have is below
> Multifix Suisse


Finally, a web site using the "correct" language 

Will


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## praetor coda

Thanks alot Angelpoisedespite buying this QCTP sometime ago, how do you think it's held up? Even now? any setbacks along the way? I figure I'll swing by and pick up a couple from this company tomorrow, is it really good? thanks for the info.


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## gadget_lover

I came across this tip, and it seems logical too.

Another way to precisely find the center of a cylinder with your drill bit.
Lay a straight edge or small ruler on top of the cylinder at right angles to the length of the cylinder.
Lower the drill bit until it is pressing on the straight edge.
If the drill is perfectly on the centerline of the cylinder the straight edge will be parallel to the table.

This is similar to the way that you can adjust the tool height on your lathe.

Daniel


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## gadget_lover

I was trying to mill a nice channel all the way around a square piece and was having a devil of a time. I figured that I'd have to put it in the vise 4 times, once for each face. This meant that I had to get it back in the vise exactly the same each time. This was not easy to do without messing up at least one face.

The solution was simple. I clamped a block to the mill's table and scooted my piece up against it each time. The vice jaw was the reference for the X axis, the block the reference for the Y axis. Cool, NO? 

They make stops specifically for locating work in a vise but I've not seen them.


Another solution was to use a slitting saw and mount the piece just once, then run the saw around it. I'd picked up a 1/8 inch thick HSS slitting saw from Enco last year but I did not have an arbor. Tonight I made an arbor from cold rolled steel. I was able to take .050 cuts in 6061 aluminum with my micro mill at about 500 RPM with no chatter and no signs of strain.

This is what that puppy looks like with the arbor I made. The arbor shaft is 3/8 inch so it will fit in my drill chuck or my end mill holder. I'm using a little piece of zip-tie as a key, since I know I have plastic gears in the mill somewhere. 





And here's the saw in action. It's cutting a piece of what I think is 7075 that was left over from a project.





There is something interesting about that cut. I just popped the scrap metal into the vice, not truing it any direction. It was clamped against a rough sawed surface and it was not vertical in any direction. Even so, the saw made 1 continuous cut all the way around. Looking at the piece, I can see that the front and back slope from one side to the other, and that the left side cut is higher than the right.





Daniel


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## gadget_lover

Well, it's time for another stupid newbie.

The task was simple. I have a 1xCR123 light that I made from 2011. It's got a 17mm reflector and is .900 inch OD. The bezel screws on to hold the lens in place. I was NOT happy with the bezel beacuse the threads were cut a little sloppy. There was just too much slop and that caused the bezel to sometimes sit off center enough that you could tell when dragging a thumb over the joint.

So I set out to make a new bezel. It's only 1/4 inch wide, .900 od, .806 id for the threads and .660 for the lens opening. The threads are .023 deep. I only have 1.125 inch diameter 2011, so I started by chucking a 3 inch long piece of 2011 and turning down the last 1/2 inch section to a bit over .900.

I rediscovered why I like this alloy. I made three passes at about .050 deep per pass. Used a TiN coated C6 carbide insert. The chips came off in a beautiful shower. I was happy. It was within .010 of target in less than 3 minutes. I thought back to last year when I was taking .010 cuts and making beautiful curls and realized I had progressed somewhat in only 12 months.

Then I drilled a 1/4 inch hole 3/4 inch deep so I could use my boring bar. Just for fun, I set it to take a .050 bite too. Within minutes it was right at .801, so I made a couple of cleaning passes to get exactly .806. Got it.

Yep, here's the stupid part. I had read that it's a neat idea to run the lathe in reverse when threading to a shoulder. The carriage moves to the right so you start cutting at the inside and finish when the bit clears the outside. That sounds like I neat idea, so I put the gear cutting lever on the back all the way down and flipped the power switch to forward. The other trick I'd heard was to mount the bit upside down when you do this AND that if you cut at the back it's easier to see.

So I did all this. The thread cut nicely, and the carriage stop I made last month worked great for getting back to the same starting point every time. I even used the threading indicator properly.

You can imagine my puzzlement when I went to test fit the flashlight and it did not fit. "Maybe another pass, say, .002" I thought to myself. Nope Still the threads did not engage. I worked on it and worked on it, cutting the threads deeper and deeper. I had hit .019 too deep when the flash light almost screwed in. Not quite, but I got 1/4 turn. It was when I went to unscrew it that I got my surprise. As I unscrewed it the body moved INTO the bezel.

Anyone guessed what I'd done? By putting the threading lever down I had cut a left hand thread. by cutting the threads deeper and deeper the whole thread of the head fit within the enlarged opening of the bezel. 

The proper procedure was to put the theading lever UP and put the motor control in reverse. The bit would be turned upside down for cutting in the front or right side up when cutting at the rear.

My lathe now has two labels. The first is towards the back of the headstock and says "Lever UP for right hand threads". The second reads "Reverse moves carriage to the right" and is right next to the on/off switch.


Daniel


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## Anglepoise

Gadget......All I can do is repeat something I said in a previous post
" You sure are having allot of fun  "


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## Anglepoise

gadget_lover said:


> I came across this tip, and it seems logical too.
> 
> Another way to precisely find the center of a cylinder with your drill bit.
> Lay a straight edge or small ruler on top of the cylinder at right angles to the length of the cylinder.
> Lower the drill bit until it is pressing on the straight edge.
> If the drill is perfectly on the centerline of the cylinder the straight edge will be parallel to the table.
> 
> Daniel



Great tip. I would also add that if you use a short stubby center drill you will eliminate any wander of the drill and get a bang on hole.


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## cmacclel

I thought C6 was only for Steel.....................c2 for aluminum.

Mac


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## gadget_lover

I can't find the reference at the moment, but as I recall, the C2 VS C6 decision is not cast in stone for home shops.

Per memory;
C2 is tougher, and can stand interrupted cuts better.
C6 is harder, but more brittle. It will hold an edge longer butis prone to chip if it hits something hard from the wrong angle.

Since my inserts tend to die of stupid things like dropping the tool on the concrete floor or clipping the tip with a chuck jaw I'm not too concerned about wearing them out early.

I use TiN (or are the TiCN???) C6 for most everything. The coating minimizes wear. I have C2 inserts for when I need them. The sharp C6 will cut steel beautifully.

David, You are right. I have waaaay too much fun with this stuff. The stubby center drill does make a big difference. First, it minimizes any drill chuck run-out. Second, it's got less length to bend. I have one that's permanently mounted in it's own 2MT endmill holder. for use on my lathe and the micromill. It's as accurately alligned as I could make it.

Daniel


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## wquiles

For aluminum, like 2024, 6061, 7075, any of these (C2, C6, TiN inserts, etc.) should work and last a long time, right?

EDIT: I recently got some new 6061 and 7075, but I ask about 2024 since I got a 2" diameter by 18" long piece for $18 at a surplus store close to me 

Will


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## Anglepoise

What do you guys use for coolant/lube on Aluminium.

I have tried many different solutions and now use a brush to apply the liquid directly to the piece and tool.

My current favourite mix is 75% Kerosene + 25% Johnson's baby oil.
The baby oil seems to cover the kerosene smell and my false edges are a thing of the past.


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## gadget_lover

By false edges do you mean the buildup on the cutting edge? I see that more with slow speeds and uncoated C2.

I drip tapmatic #1 gold from a squeze bottle for parting, and either drip or brush it on when turning. It has a pleasant smell. I often turn dry if I'm making rough cuts. I know that's not right but......

I don't use enough for it to act as a cooant.

The uncoated C2 does dull faster than I thought. I used one for 4 or 5 months and did not realize that it was getting progressively duller till I tried to cut some mild steel. IT just would not penetrate. I rotated the insert to a fresh edge and it cuts fairly well.

BTW, I mark my inserts with a paintpen when I rotate them so I can see at a glance that (for instance) insert A is new and insert B has only one fresh cutting surface. 

Daniel


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## Anglepoise

gadget_lover said:


> By false edges do you mean the buildup on the cutting edge?
> 
> Daniel



Yes..............the build up on the tip. Mostly when turning aluminium with carbide or HSS.


----------



## gadget_lover

I see the false edge most often on my boring bars. I tend to run it a bit slower when boring, so it's not too suprising. The boring bars are HSS and uncoated C2 (IIRC). I need to remember to use cutting oil when boring.

The tapmatic has an slmost sweet small to it.
EDIT** The Tapmatic fluid has an almost sweet smell to it. SHEESH!

It is sold as "cutting fluid" but I use it for taping as well as for cutting aluminum. It does not smoke too badly.

Daniel.


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## scott.cr

I didn't read this thread 100% to its entirety, but there's another way to find TDC when drilling and milling tube and round rod.

Clamp a V-block to your table or vise. The V-block has a "ditch" in it at the point of the V. Lower your center finder or drill bit until it's in the ditch of the V. That's your center. Then just drop in your round work and drill or mill away.

V blocks "should" be very square and parallel... so you can true it up to your X-Y table with a dial indicator to make sure you still remain on-center when slotting or fluting.


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## gadget_lover

Thanks Scott. I never think of the V blocks. I wonder why?

Stupid trick of the day.

I finished that stupid bezel tonight. It came out great, BTW. I used the technique where the threading lever is UP and the switch is thrown towards "reverse". The threading tool was face up but bearing against the back of the cylinder because teh chuck was spinning in reverse. It was sweeeet!

Before parting it off I decided to bore the center hole just a tad deeper so I'd have room to play if I needed it. The boring tool just kind of chattered. I looked in and saw that the previous boring had taken it down to a flat surface. I chucked up the 1/4 drill bit and mounted the tail stock. I was flabergasted when the drill would not bite. It barely raised a chip no matter how much pressure I put on it. I changed bits and it still would not cut.

I had many thoughts including dull bits, sliding tailstock and work hardened aluminum. As I turned to get the Drill Doctor off the shelf I saw the forward/reverse switch was still in the reverse position. 

I can now positively say that neither boring bars nor drill bits will cut anything if the chuck is going clockwise.

The newby trick? If you get NO bite from your tool you should check the direction of rotation.

Daniel


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## gadget_lover

Silly newbie trick Courtesy of HarryN.


There are several ways to hide the joint where two pieces go together. I'm going to spend a few minutes talking about some of them. I'd love to hear of other tricks.

Background:
Whenever you join two pieces of plastic or metal you are left with a line. You may also have a slight mismatch in the sizes where they join. Sometimes the alignment is so good that all you see is a hairline. Sometimes you can barely see it but you can feel it with a fingernail. What to do? 

This is one of my earliest joints. You can see halfway up the light is a ring that is easy to see and feel.






There are several avenues that you can take. In no particular order there is camouflage, deliberate mismatch and alignment guides.

Camouflage;

The concept is simple, and it's been used in many of the popular CPF lights like the groovy, the VIP and lioncub. The body of the light has grooves or other decoration around the circumference. The joints are placed at a the edge of such decoration. The edges provide a natural line, so one more line is no biggie.

Here are three lights that use this technique. The VIP on the right has so many rings that you don't see the joints at the bottom of the grooves. The VIP actually has 4 joints (IIRC) hidden in there. The Surefire in the middle also uses many decorative rings in their design. The exact point where the tailcap starts is not obvious from the picture due to the other grooves. The knurled band on the gerber on the left is (visually) similar to the gap between the head and the body. Instead of looking cheap it looks like it was part of the design.






Deliberate Mismatch;

The next trick is really quite useful. Instead of trying to match the exact diameter of two pieces, you simply make the mating parts different enough that the mismatch is obviously by design. The Surefire uses this alot. The hexagonal piece on the head, for instance, mates to a smaller scalloped piece. It requires no precision at all.

A related trick is to make the joint obvious. Make it stand out. Make it bold! Again back to the surefire. You can see the joint where the bezel meets the head. It's got a huge gap there to disguise the much smaller gap from the joint. There is no where that the parts have to match diameter. Only examining it in a good light will disclose the "only average" fit. In the case of this specific light it also hides the fact that the bezel was not perfectly aligned with the threads. The gap is slightly larger on one side of the light than it is at the other.

Here is another case of "make it obvious". The light is only 3 inches long. The parts all match fairly well less than 1/1000 off at any point. I beveled the edges of the matching parts, making the joints obvious, moving the matching edges away from each other and making them part of the artistic (ha!) design.





Alignment guide;

This trick is courtesy of Harry N. I made a light that screwed together at the tailcap. I carefully matched the diameter, looking for a perfect invisible joint. I sanded and polished until you could not tell the line was there by sight or feel. The first time I changed the battery I almost cried. The parts were no longer aligned when I screwed it back together. 

Threads have to have some play in them. If they were a perfect fit you'd have trouble using them as any dirt or other buildup would jam it. This works against you when you try to make two parts fit properly. The play in the threads allow the parts to shift to the side, ruining the axial alignment.

It was HarryN who pointed out that the simple solution was matching bevels on the parts. The bevel will align the parts as they close together. Assuming the bevel is concentric, the parts will screw together the same every time. This is that same light (on the right) after adding the bevels. The joint is 1/2 inch from the bottom of the black tailcap. 







If you have problems envisoning this.....











If the parts are beveled like this, you can even put them back in your lathe and turn a fresh surface that is absolutely concentric and the same diameter across the whole length.

Daniel


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## scott.cr

Whoa, that IS a neat trick. I'm going to try it. The way I've usually done this is with a straight seating shoulder. It works, and looks good, but if there's a nick on the shoulder you can forget about getting that joint back together.


----------



## gadget_lover

Nicks are a problem, but you can use a small jeweler's file to remove the part that stands out if it's on the male side. 

You can use a square seating shoulder along with a taper. It just takes a bit of fitting to get everything touching at just the right spots.

One thing that screwed me up doing this was threading the female part all the way to the edge of the taper. The female thread has to stop before it reaches the taper, otherwise it can hit the male taper on one side first and keep it from seating correctly.

This light is a new copy of my "slim2" design. I made the seams fairly invisible using the bevel method. It's not bad, considering I screwed it up a dozen times while making it. The final finish cut was made with the parts screwed together. It's raw aluminum (2011) without polishing.






Daniel


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## gadget_lover

Here's a tip I read the other day. Too bad my wife had already discovered it.

But first the background. Turning cold rolled steel is no more difficult than turning aluminum. The speeds are different, and you should use sightly different angles on your tools. Even so, you end up making little bitty curled chips, just like when turning aluminum. Just like aluminum, you get showered with the chips while you are working. Unlike aluminum, the steel chips have sharper edges so you have to clean up better.

Fast forward to the day after laundry day. My wife asks me if a pen leaked in my pocket. I look, and there are brown stains at the bottom of my pocket. Further investigation shows little curls of steel nestled in the folds of fabric at the bottom of the pocket. Rusty little curls. That shirt is now a "work" shirt.


Oh? The tip? Don't turn steel with exposed pockets. A shop apron ($2.95 on sale at Enco) or coat will keep the swarf out of your clothes washer. If all else fails wear a dark shirt. 

Daniel


----------



## gadget_lover

This week's newbie trick is actually an oldie.

As usual, the setup first.

I have some 1.25 inch hex bar that I wanted to use to make some bezels. I made a lot of chips knocking off the edges. A literal shower of hot chips poored off the tool. When you are making agressive cuts the chips take the shape of thousands of little curlie-Qs. Using the big black carriage handwheel lets you move the tool fast enough (right to left) to keep the chips flowing.

I had finised the first two passes (which took off the corners) and halfway through the next when the carriage got hung up. I could move it to the right, but it stopped at the same spot each time I moved it to the left. This was not the first time I had this problem. I checked the tailstock to see if it was hitting the compound. It was clear. I checked the ways for obstructions. I checked for obstructions under the back of the ways. Eeverything was clear.

That's when I remembered that the gears that move the carriage are open on the side facing the chuck. Sure enough, a lot of chips had fallen into the gear. One of them was in the teeth of the gear. Since the chip was substantial ( I was taking agressive cuts) the chip jammed the mechanism.

OK, the newbie trick. The modification at the following link does a good job of keeping chips out of the gears. I'd done it once before on my other lathe and forgot that this one needed it too.

http://www.mini-lathe.com/Mini_lathe/Modifications/modifications.htm#Chip_Guard

The hole size is not critical. I drilled it on my drill press using an 11/16 bit. You don't have to use screws to attach the shield to the apron. You can use glue if you want since there is almost no load on it. Let me know if instructions are needed for getting the apron off the lathe.

Daniel


----------



## wquiles

Since I am still a beguiner, I still come back and read this thread from time to time. It takes me several nights to re-read it, but it is always worth it, since every time I pick up one or two things that I can use right away 

Thanks to all who have contributed so far :rock: 

Will


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## scott.cr

Hah, something similar happened to me (carriage stopping). Except I had the leadscrew engaged and was threading a piece of 12L14 rod. A large curly-Q of 12L14 wound around one of the handwheel gears and managed to stop the carriage while the leadscrew was engaged. Let's just say the noise of plastic mini-lathe gears turning to plastic dust was nowhere near as loud as the expletives that left my shop that night.  The air was blue.

After that, I made the gear cover (out of aluminum, on the mini mill) and put a "torque fuse" Woodruff key on the little gear at the end of the leadscrew.


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## gadget_lover

When CPF changed to the new software the indexes were lost. This makes searching almost useless for older threads.

Here's my attempt to get the major posts in this thread indexed. I raed though every post. My typos are sometimes sooo embarassing.

Topics so far:

change gears position
change gear pivot
chuck jaws hit cross slide
unlisted change gear combinations mean more threads
centering with a 3 jaw chuck
Using a thread guage
zeroing the cross slide index for repeatable cuts
Storing QC tool holders on a rack with matching dovetails
Wood blocks as tool storage for round shank tools
Camlock tailstock pictures
Why you buy stock that is close to your finished sizes.
Extruded tubing is not always round
Drill as much as possible (in steps) before boring.
Sliding/rotating the piece as you tighten the 3 jaw helps alignment
Longer parts (more than a few inches) need a center to support the far end
Longer parts need lighter guts to prevent deflection
Upside down compressed air can works as freeze spray
Long stock protruding out of the headstock will deflect and bend
Disk sanders and grinders can make metal pieces very hot, over 400 degrees
Never catch a part that falls. It may be hot/sharp/etc
A steady rest, a follower rest and a live center help with long pieces
The QCTP screw will work with the original tool post with an adapter.
Cutting threads technique using forward/reverse switch
Cutting threads technique using threading dial
You can cut up to .050 per pass on a HF 7x10 if the tool is sharp
Turning speed (SFPM) makes a difference in finish and cutting depth.
Formula for Surface Feet Per Minute (SFPM)
Clean the stock before placing it in the chuck.
Clean the chuck jaws between uses.
Warnings about how not to polish aluminum
Parting tool tips. Centering, grinding, etc.
Tall people need tall workbenches to avoid back ache.
Home made mill bit from cost carbon steel drill bit
Adjusting height of tool using a rule.
Parting tool adjustment
Parting tool rake
Using shims to adjust height of lathe tools
Cautions about use of threaded holders for flashlight parts
Using a micro mill. Limitations.
Using the end and sides of end mills to face surfaces.
Extruded square aluminum usually has a bulge on one or more sides.
Using Dial Indicators (DIs) with a lathe or mill
Using a Test Indicator (TI) with a lathe or mill
Adding a DI to a micro mill as a poor man's DRO
Slot cutting using a mill and a Dremel High Speed Cutter
Using a sleve to protect threaded or delicate parts in a chuck.
Making a tapered tap into a plug tap
Caution when ofsetting a part that extends through the chuck body.
Mark the position of stock in the chuck so you can put it back if you rechuck
How to calulate offset to turn lobes in a 4 jaw chuck.
NEVER do any work that needs a little presure on a thin walled piece
Use arbors or collets for small finsihed pieces
Caution that compressed air will blow sharp swarf around
Caution that freeze spray may ruin temper or anneal
Proper use of coolant fluid
The importance of clamping your work
Caution about magnetic tool holders and swarf accumulation on tool bits
Choosing Boring bars for a small lathe
Boring heads for mills
Knurling with and without calculating
Dorian knurl cutter
Knurl borders
Determining threads for blind or recessed holes
Using Cerosafe to determine thread dimensions on difficult holes.
Using the change gears for a mini-lateh power feed.
Marking change gears for easy identification
When you make a plan for turning, don't deviate without updating the drawing.
Centering a mating part by adding a bevel
The impact of leaving the threading lead screw turning.
Mark the lead screw so there's a visible indicator when it turns.
Tight connections when the end mates with a shoulder, not jut run out of thread
Inserts and how they are used.
Cross slide will hit the tailstock base without being obvious.
Insert identifiers and their decoding
O-ring selection and differences in appliactions (rotating VS static)
O-ring sources
Using Morse taper collets to hold drills in the tail stock to get more room
Drill lengths - jobber/screw machine/taper/aircraft
Drill sizing Lettered, numbered, fractional and metric
Caution to wear safety glasses
Caution to clean swarf from lathe tray before it's flung about by the chuck
Description of a flywheel ironworker to punch holes in I-beams
Caution to waer mask when turning cast iron. Lots of dust inhaled.
Suggestion to use water as coolant when turning cast iron.
Use oil on steady rest 'fingers' to minimize scratching
Always do knurling before boring.
Procedure for facing on infeed as well as outfeed.
Suggestion to support long pieces through headstock by hand
Caution about burrs when supporting pieces by hand
Compound can hit live center without being obvious
Cutting up to 9 inch long piece on a 7x10 lathe (remove pillow block)
Turning a 4 inch faceplate for a chuck
If you think something slipped, stop and re-measure
Making a bezel, right, the first time using matching threads
Measuring dovetails using rods and a caliper (duplicating dovetails)
Using calipers. Inside, outside, depth and to a shoulder
Digital caliper mods. Cut down and removing 'depth probe'
Quick and dirty height gage made from wood and digital caliper.
Surface plates and their uses.
Lay out dyes / layout fluids (Dyekem)
acetone as a Dyekem remover
Dremel + zip tie + parting tool holder = temporary tool post grinder
mechanic's square for aligning things like compounds, parting tools, etc.
Things NOT to do when cuttingh threads
Using a wiggler to center within a hole
Co-axial indicators used to precisely center on a hole
Centerpuch hole locations before using a wiggler.
Turning wood on a HF 7x10 (pens, flashlight cases, etc)
Setting the compoung to 29.5 degrees from paralle to work axis.
Cutting threads using compound set to 29.5 degrees
Using a drill press motor for a Tail lathe
Using a wiggler to find the equidenstant poing between vice jaws
Use two chucks to swap between parts with out losing alignment.
29.5 is really 60.5 to infeed axis
Using a window shade for a temporary backdrop behind lathe
Conserve Digital caliper batteries by removing them at the end of the session.
Using a carriage stop
Making attachments for "v ways" (90 degree tilted 45 degrees)
Caution about sealing aluminum by boiling 
Using a lathe as an indexing gig with a 3-in-1 machine.
Small rotary tables
Replacment shopvac hose.
Reason for rotary table holes.
Using a dial indicator to center a tube under a mill/drill
Using a rule to center a tube under a mill/drill
Using a V block and clamp to center a tube under a mill/drill
Using a 1-2-3 block as a work stop on a mill table
Using a slitting saw in a micro mill
Turning left hand threads
Using C2 VS C6 inserts
Cutting fuild favorites
Mark inserts as you use each edge
Symptoms when the lathe is running in reverse.
Making joints that are not noticed camoflauge/bevels/mismatch
Dark shirts hide rust stains from steel swarf in the pocket
Adding a shield to the carriage gears so they don't jam.


Daniel


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## Christexan

Hope no one is offended at me bringing this thread out of "retirement", but had a lot of fun reading through it... 
I'm not a machinist (wish I had the tools, money, and time to learn), but regarding the "hiding the joints" tricks, a trick that might help from finish molding techniques...
The mating bevels trick described is wonderful, especially for linear alignment, but doesn't solve the problem of "perfect matching bevels" needed to make a perfect external joint (of course, practice makes perfect, but my proposal is a "quick and dirty" idea....
Instead, make the shoulders just a fraction less (backcut from out to in) than perpendicular on BOTH sides of the joint (literally to the finest fraction you can adjust so that the angle goes slightly "back" from the outside to the inside)... 89.9 degrees, something like that.... 
What this does, when the pieces are threaded together (or in moldings, joined in a corner for instance), this "backcut" on both sides makes the only hard contact point the external visible surfaces, so they will tightly mesh together. (Don't backcut too much or the edge of the joint will be weakened, the tiniest bit will do the trick without compromising too much edge strength hopefully)... nicks and wear however will actually become a bit more visible over time, since there is a normally invisible "gap" behind the surface (again, minimizing the backcuts minimizes this effect). 
If well made, this joint probably be virtually invisible, lost in the toolmarks of a "final surface" preparation. 
I don't know any of this would work well for sure, wanted to put it out there to see what ya'll think (or if this is nothing new and is "lathe-101", then I apologize)


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## gadget_lover

Of course we don't mind resurrecting a thread. We have some that lie dormant for a full year before new posts bring them back to life.

The back-cut's an interesting idea. I've sat in restraunts and marveled at the crown molding with almost invisible seams. It might work well with threaded cylinders too.

Thanks!

Daniel


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## Anglepoise

Back cut sounds interesting. I try and use the deign elements to my advantage.
I will make the join at the transition of a groove or knurl band.
My best results have been with the join in the corner of a groove.

Also I like the idea , and have used it a couple of times, to re turn the O.D.
with the threads screwed together. Then the fingers will not feel the joint.

Good to see you around 'Gadget'. Have missed your tips.


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## gadget_lover

Thanks David. The new job leaves no time to play. I had to get a cellular modem just so I can read CPF while commuting {on a train}.

I have the itch to create, so I will be doing something soon. 

The SNT (silly newbie trick) ; It's hard to grip tapered and irregular objects in a vice. A small rod between the slope and the jaw can allow you a 'good enough' grip as long as you secure the part from sqirting out.

Daniel


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## gadget_lover

I was chatting with with Will, another CPFer about collets. He and I both use the ER series of collets. Those are the ones that are spring collets that cover a range of almost 1/16 inch. A 1/8 inch collet will hold a 3/32 inch rod, for instance. Both of us found it was hard to get a 3/4 inch rod (nominal) into a 3/4 inch collet.

Will pointed out that the 3/4 inch rod was larger than 3/4 by a few thousandths. He also pointed out that the 3/4 inch collet sold by ENCO had a range from 0.708 to 0.748 instead of the 0.708 - 0.751listed for other sellers. 

So it made sense. I'd been forcing 3/4 inch parts into my .0748 collet. No wonder it was akward at times.

The silly newbie trick ;

Figure out the maximum size for yor collets. It's easy to do. Use a caliper to measure the hole while it's not in the collet chuck. If appropriate, print out the chart from Enco's catalog and keep it with the collets. It may be necessary to create your own chart. 

II bought cheap collets, so in my case, the size marked on the collet is tsize that is too big for the collet.  

BTW, you can not just grind out the collet, since if you do that the SMALLEST size that the collet will hold will now be bigger than the next smaller collet.

A quick list from Enco for the ER series of collets;


Code:


1/32    0.020    0.040 
1/16    0.040    0.080
3/32    0.080    0.120
1/8     0.120    0.160
3/16    0.160    0.200
7/32    0.200    0.236
1/4     0.236    0.275
5/16    0.275    0.315
11/32   0.315    0.354
3/8     0.354    0.393
13/32   0.393    0.433
7/16    0.433    0.472
1/2     0.472    0.511
17/32   0.511    0.551
9/16    0.551    0.590
5/8     0.590    0.629
21/32   0.629    0.669
11/16   0.669    0.708
3/4     0.708    0.748
25/32   0.748    0.787
13/16   0.787    0.826
27/32   0.826    0.866
7/8     0.866    0.905
15/16   0.905    0.944
31/32   0.944    0.984
1       0.984    1.020


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## dom

Hi Daniel -Sounds like your collet set is a re-marked metric set -the 0.708 to 0.748 works out to 18-19mm.
The other sizes seem to correspond to whole metric numbers as well.
Not that helps much -unless you decide to go metric with cutters and such 

Cheers
Dom


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## gadget_lover

Thanks for that insight Dom. It makes sense. The ER specs I find in Machinery's Handbook are all listed in MM instead of inches and it looks like it's a DIN standard. I always feel better when something makes sense.

Daniel


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## PEU

bump for a great & informative thread.


Pablo


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## gadget_lover

People often ask about whether they should get a small mill or a big one. There are many, many things to take into account, from power requirements to floor space to cost of moving them.

I've used a micromill (less than 100 pounds and 18 inches high) for about 3 years. It's been a great learning experience.

I just recently got my new 8x30 knee mill working. I did a few test cuts before I got down to trying to actually use it, and I loved the way I could hog out great big bites with my largest end mills. A 3/4 inch wide, 1/4 inch deep cut down the middle of 12 inches of 6061 -t6 in one pass.  

And now the silly newbie part.

It was not till a few days later that I noticed that I had an infestation. Little silver glints throughout the house. Yep, the swarf that I had so carefully swept up had managed to spread, embedded in clothes and shoes.

I'd not had a major problem with migratory swarf when using my micrimill. It was not till I looked at them closely that I realized why.

The chips on the left are a product of the light cuts I make with the micro mill. The chips on the right are from the new mill. The battery is an AA just there for size reference. The smaller chips are so flimsy that they squish when stepped on, and easily brush off my clothes. 






The heavier cuts on my big mill cause bigger, sturdier chips with sharper edges. The embed into my shoe soles, and they snag in my clothes until dislodged by a firm contact.

If you have an apartment or other area where swarf might be a problem, then there is one more point in favor of a smaller mill.

Daniel


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## gadget_lover

I've lusted after a nice 'set-true' since the first time I saw one. They solve a very basic problem of scroll chucks....


The problem: Scroll chucks are not very accurate. When you change the jaw position the imperfections in the scroll subtly change the relative position of the jaws.

A set true chuck has an adjustment built into the mount to allow you to shift the chuck a few thousandths in each direction.

The person in the attached video found that there was enough slop in a typical small lathe to allow you to shift the chuck around. He shows how you can use a ground rod ( in this case a large drill bit ) and a dial indicator to get the chuck pretty well centered for that particular diameter.

http://www.youtube.com/watch?v=Hi_s0iQkRFA


Wish I'd thought of that. 

Daniel


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## Mirage_Man

gadget_lover said:


> I've lusted after a nice 'set-true' since the first time I saw one. They solve a very basic problem of scroll chucks....
> 
> 
> The problem: Scroll chucks are not very accurate. When you change the jaw position the imperfections in the scroll subtly change the relative position of the jaws.
> 
> A set true chuck has an adjustment built into the mount to allow you to shift the chuck a few thousandths in each direction.
> 
> The person in the attached video found that there was enough slop in a typical small lathe to allow you to shift the chuck around. He shows how you can use a ground rod ( in this case a large drill bit ) and a dial indicator to get the chuck pretty well centered for that particular diameter.
> 
> http://www.youtube.com/watch?v=Hi_s0iQkRFA
> 
> 
> Wish I'd thought of that.
> 
> Daniel



Yep, that looks like it would be one way to go if you don't have a Set-Tru.

I do happen to have a 6" Set-Tru chuck. I just got a 6" long piece of 1" Thompson precision shafting and was able to dial the chuck in to around .0002" TIR. I could have probably gotten it closer but I think that's good enough for government work :naughty:.


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## Anglepoise

This must be our longest running thread.

Glad to see it again.....


The idea of just using the 3 bolts for locating the chuck on it's back plate has been around for a long time.

My only objection to the method used in the video, is its very slow.
Tapping with a rubber mallet can speed the whole process up considerably.

Unused Piston pins make excellent truing devices and are available from any engine re builder for a nominal charge. 

The only thing one has to remember with a set true or the method described above........it only works at the diameter of the ground and true test piece.
Adjust the chuck 1/2 inch away in either direction and you will be back to the chucks original runout .


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## will

Anglepoise said:


> My only objection to the method used in the video, is its very slow.
> Tapping with a rubber mallet can speed the whole process up considerably.
> .




Or a plastic mallet....


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## gadget_lover

will said:


> Or a plastic mallet....



+1 on the mallet.

I think that the thread has run so long because there is so much for a newbie to learn.



Like getting a good finish when using the mill. It never occurred to me that the end mill you use for roughing might be dull enough to impact the finish on your part.

So reserve a set of end mills for roughing, and another just for finishing. When the finishing mills start to wear, rotate them to the "roughing" set.

Using the right FEED makes a huge difference too. While there are formulas that tell you how many Inches Per Minute (IPM) of feed to use when milling, they generally lead you towards the maximum speed that you can handle when cutting metal. Take it a little bit further and you finds that the finishing pass IPM is REALLY slow. Like an inch per minute when the spindle speed is 300 RPM. 

This and MANY other good tips from http://www.cnccookbook.com/MTMillSurfaceFinish.htm

Daniel


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