# Some lathe questions?



## vestureofblood (Jan 7, 2012)

Hey all,


I have a few questions about choosing a lathe. The most important ones would be these.

1. Are there mini lathes that can chuck a maglite?
2. Will a typical lathe be able to cut threads on the inside or out of a mag body, or is that strictly CNC type stuff?


Thanks.


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## gadget_lover (Jan 7, 2012)

Thanks for asking questions that I can actually answer. 

1) a mini-mag will fit within the chuck and spindle bore of a 7x10 mini-lathe. Will made a nice adapter that a C ( or was it D???) sized mag would screw onto. My 4 inch chuck will hold a D sized mag on my 7x10, but doing precision work on the far end requires the use of a center in the tailstock or a steadyrest. Will also had a nice fixture that he made to mount the Mag heads while he was finning them.

2) A typical lathe can cut threads on any cylinder that can be held securely. The closer you are to where it is supported, the easier it is to do good threads. 

There have been many threads in this forum on the subject of "What lathe should I get for flashlights." In general, big is best. With ingenuity and extra work, you can do a lot with even the smaller ones.

Daniel


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## StrikerDown (Jan 7, 2012)

The only thing I miss from my 7 X 10 Mini is the variable speed. 

My 14 X 40 is big enough for most things I do, but would be nicer with a big bore spindle and variable speed!

Look closely at the mini lathes before you buy. Only small sizes can pass through the headstock and if you are working with a chuck in the tail stock there isn't much room for a drill bit and the part to be drilled! Smallish items are fine because usually you will be removing only small amounts of metal. deep or heavy cuts are out because the mini isn't very rigid or powerful. 

What ever you decide to buy try to get the largest you have space and budget for, it is most often the cheapest way out in the long run!


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## tylernt (Jan 10, 2012)

gadget_lover said:


> 1) a mini-mag will fit within the chuck and spindle bore of a 7x10 mini-lathe.


An 18mm diameter AA Mini-Mag won't fit through the 16mm opening of the 3-jaw chuck my HF 7x10 came with. Now, AAA Mini-Mag, or in a 4-jaw, I believe those will fit.



> Will made a nice adapter that a C ( or was it D???) sized mag would screw onto.


Owing to the difficulty of machining 4-start threads, I plan to just sacrifice a spare beat-up Mag-lite to use as ready-made head and body "adapters". 



StrikerDown said:


> if you are working with a chuck in the tail stock there isn't much room for a drill bit and the part to be drilled!


Yeah, I got the 7x10 from HF because it was on sale and in stock locally. I immediately hit that drill length problem, so I'll have to get or make some "stub" drill bits in the larger sizes. If you haven't bought a lathe yet, it's well worth a few extra bucks to get the 7x12 or 7x14.


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## gt40 (Jan 11, 2012)

I struggled with this a year or so ago. I recommend you get a size larger if you can, than the 7x10's. It isn't about size for flashlights, it is about having enough rigidity and power to make a light with a reasonable amount of time. I am amazed by some of the work people can turn out with the mini lathes. I started with the harbor freight 8x12 and it was okay size wise but power and rigidity are limited. I fell into a 13 x 40 Jet and it was an eye opener. I may never turn large stock to take advantage of it of the giant size but i can do more in one pass than many passes on the 8x12. Keep in mind the 8x12 is a step up from the 7x10 mini lathes. Good luck and consider the 8x12, c4, c6 or 9x20 size.


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## Maglin (Jan 11, 2012)

I was in the same boat just over a year ago. I wanted a mill I could CNC and a lathe to turn the ballscrews and make parts and tools for the mill. I got a 11x27 lathe and was happy with it. I originally was going to get the G0602 10x22 from grizzly but went with the PM lathe cause it had power crossfeed. I was happy with it but I couldn't take large enough cuts on it and certain parts that required a decent amount of metal removal took what seemed forever to machine. I just upgraded to a PM1236 and I couldn't be happier. It's far more rigid and can take some pretty serious cuts. Personally if I had the budget I would have gotten a 1440 lathe, and plan to get one in the coming years.

If I was to have to recomend a lathe to someone starting out I would point them to the http://www.grizzly.com/products/10-x-22-Bench-Top-Metal-Lathe/G0602 Lathe. It's the smallest lathe I would go with and it's not to much money.


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## vestureofblood (Jan 11, 2012)

Ok I am starting to get a feel for what I might need. 

From the looks of it finding a mini that will throat a D cell maglite is not easy. Is "Spindle bore" the determining factor in making this possible?


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## precisionworks (Jan 12, 2012)

> Is "Spindle bore" the determining factor in making this possible?


Yes and no 

Swing determines the maximum diameter of the chuck that can be mounted & bigger chucks have larger bores. My 14" lathe takes an 8" 3-jaw or a 10" 4-jaw and both are over 2" bore through the chuck ... but the spindle bore is only 1.875".


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## vestureofblood (Jan 12, 2012)

Ok, that is actually very encouraging. Lets see if I am catching on here... The set of numbers say in an 8"x12" lathe, the first number ( in this case 8") is the "swing" meaning from the center of the chuck to the base of the machine is 8" clearance? The second is from the tip of the chuck to the tail, meaning the max length of clearance for the materiel used? 

If this is correct then I am assuming that the max size chuck for a lathe is determined by how far out the jaws extend past the head when its wide open? In this case I am guessing that a 6" chuck would exceed that in an 8" lathe?


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## precisionworks (Jan 12, 2012)

> the first number ( in this case 8") is the "swing" meaning from the center of the chuck to the base of the machine is 8" clearance?


Swing describes the largest diameter part that can be turned (swung) over the bed, so an 8" swing machine has 4" radial clearance from center of chuck to bed. A 6" 3-jaw or 8" 4-jaw is the biggest size that can be used on a 12" machine.

OK, you could mount an 8" 3-jaw on a 12" lathe ... as long as you don't open the jaws :nana:


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## gadget_lover (Jan 12, 2012)

Notice that Barry said 'from the center of chuck to bed". Note that the compound is often several inches above the bed, so you have 'swing over bed' and 'swing over cross-slide'. 

Examples:

My 9 inch swing lathe can hold a 9 inch round between the saddle and the chuck, but only a 6 inch cylinder from end to end. 

My 7x12 can turn a 10 inch section of a 5x12 cylinder (going from memory there) since the saddle only moves 10 inches ( left to right ). It can face a 7 inch round.

Daniel


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## vestureofblood (Apr 15, 2012)

Ok it still seems that even by going to a slightly larger lathe than I first intended the major stumbling block is still the spindle bore. Even the mid size lathes seem to have only a measly 1" bore. Which still does not get me to where I need for a D mag.

Is it possible to change the spindle on a lathe rather than just the chuck, or is that a huge ridiculous unheard of thing to do?


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## tylernt (Apr 15, 2012)

I don't believe enlarging the spindle is going to be possible. You don't need a big through-spindle to machine D Mags, though. Just add a steady rest. Even a 7x10 lathe will machine a D Mag with a steady, though you'll run out of length for boring anything longer than a 1xD. If you've got the bed length to do what you want, swing doesn't matter once you add a steady rest.


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## 350xfire (Apr 15, 2012)

Yeap, you'll probably need a minimum 12" swing lathe to have a 1.5" spindle bore size.


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## BVH (Apr 15, 2012)

Don't forget the PM 1127LB with 1.5" spindle bore.


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## 350xfire (Apr 15, 2012)

Ah, nice!


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## precisionworks (Apr 16, 2012)

vestureofblood said:


> Is it possible to change the spindle on a lathe rather than just the chuck, or is that a huge ridiculous unheard of thing to do?


A large spindle bore means a correspondingly large outside diameter. The bigger OD means larger bearings & those would have to fit into larger bearing seats.

Possible? Sure. Practical? No way. You'd spend as much money doing that as the lathe cost.


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## vestureofblood (Apr 23, 2012)

tylernt said:


> . Just add a steady rest. Even a 7x10 lathe will machine a D Mag with a steady, though you'll run out of length for boring anything longer than a 1xD. If you've got the bed length to do what you want, swing doesn't matter once you add a steady rest.



So is it better to get a rest that just has the rods sticking out or do I need one with the barring/wheels? I'm guessing some masking tape around the mag to protect the finish would be needed?

EDIT: Could someone also give me an idea of what bits/tools I'll need to do a cut down rethread of a D mag?

Possibly a link for the bit with the thread size I'll need for that?

EDIT AGAIN:

There are a couple of items I found locally, if anyone wants to give some input, they are both listed for about the same price. If the one with the mill (enco109-1005) would thread I sort of thought that may be the way to go, but the 9x19 grizzly seems like a good option too.

Any suggestions where my money would be better spent?


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## tylernt (Apr 23, 2012)

vestureofblood said:


> So is it better to get a rest that just has the rods sticking out or do I need one with the barring/wheels?


For general machining, the steady rests with solid brass fingers that rub on the work will damage the finish, but are more rigid for taking heavy cuts in tough materials. The steady rests with wheels/bearings don't mess up the finish as much, but when cutting on the OD sometimes swarf rolls under the wheels and scars the finish anyway.

For a Mag boring / internal threading operation, no swarf should end up anywhere near the rest rollers. Plus, shallow cuts on aluminum do not require a lot of rigidity, so the roller type is the right tool for this particular job.



> I'm guessing some masking tape around the mag to protect the finish would be needed?


Exactly. I'll be making my own steady rest for my 7x10 (factory rests don't open big enough), and I'm toying with the idea of making PTFE (Teflon) tipped solid fingers. With a drop of oil, these should not mar anodized aluminum so I won't have to use tape. If that doesn't work for some reason I'll go to tape and rollers.



> EDIT: Could someone also give me an idea of what bits/tools I'll need to do a cut down rethread of a D mag?


You'll want either a parting tool to shorten the tube, or, you can shorten it with a hacksaw initially and then clean up the edge on the lathe with a standard facing tool.

You'll also need an internal grooving tool to make a thread relief (a place for your thread to end) and a boring bar to open up the ID on the end of the tube to make a place for the tailcap O-ring to go. Depending on what you buy, you might be able to do both of these operations with one tool.



> Possibly a link for the bit with the thread size I'll need for that?


Unlike taps, all you need is one single-point internal threading bit. When single-pointing on a lathe, you can cut any diameter of thread and wide range of thread pitches all with the same single-point tool. I don't know the C/D Mag thread pitch off the top of my head, but I imagine most internal threading bits you might buy will be able to cut that pitch.


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## tylernt (Apr 23, 2012)

vestureofblood said:


> There are a couple of items I found locally, if anyone wants to give some input, they are both listed for about the same price. If the one with the mill would thread


As long as the all-in-one machine has a powered geared leadscrew, it can cut threads. Not all of them do, so you'd have to research that particular make and model.

As for which is better is a tough call. All-in-ones tend to be good lathes and poor mills. A pro machine shop that needs to mill large steel parts would never even consider one. But if all you're doing is light milling on small flashlights for a hobby, it's probably entirely adequate -- at least as good as a lathe with a milling attachment.


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## PCC (Apr 23, 2012)

tylernt said:


> I don't know the C/D Mag thread pitch off the top of my head, but I imagine most internal threading bits you might buy will be able to cut that pitch.


I'm pretty sure that they both use 20TPI. The C-Mag _might_ be 28TPI, but, don't take my word for it.


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## vestureofblood (Apr 23, 2012)

tylernt said:


> As long as the all-in-one machine has a powered geared leadscrew, it can cut threads. Not all of them do, so you'd have to research that particular make and model.
> 
> As for which is better is a tough call. All-in-ones tend to be good lathes and poor mills. A pro machine shop that needs to mill large steel parts would never even consider one. But if all you're doing is light milling on small flashlights for a hobby, it's probably entirely adequate -- at least as good as a lathe with a milling attachment.




Ok here is the situation on the mill one. I contacted the seller and he knows about as much as I do ( not much). His cousin gave him most of the info on it after he acquired it for doing some work.

He didnt know if it had a powered geared leadscrew, but he said his cousin told him it has auto feed toward the material and that it is thread cutting capable. So that means It will work for what I want correct?

The other problem I see with this is will it be possible to get a steady rest for this machine??? I tried to google it but was unsuccessful at finding one. I'm not trying to be lazy, I dont mind doing research for myself, but it seems like if I am going to get one of these time is a serious factor here and I dont want to blow this. Any help I can get is appreciated.


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## 350xfire (Apr 23, 2012)

You will find that you will quickly outgrow the 9x machine... As for steady rest, those make contact on the piece so they will cause scratches. Unless one can rig up some type of spacer to serve as the contact point.
What is the price on those machines? I would prefer to do the one without the mill. You will also quickly find out the limitations of a combo unit like that. Although some people may like them.


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## tylernt (Apr 23, 2012)

vestureofblood said:


> He didnt know if it had a powered geared leadscrew, but he said his cousin told him it has auto feed toward the material and that it is thread cutting capable. So that means It will work for what I want correct?


Yep it sounds like that should work. On the left side there should either be levers where you can change the thread pitch, or, a set of change gears. If this machine uses change gears, make sure the machine comes with the rest of the set of gears! If they are missing, obtaining replacements will be a real hassle.



> The other problem I see with this is will it be possible to get a steady rest for this machine???


Steadies are generally specific to one make and model of lathe. Lathe bed dimensions are just to different to allow for a universal fit. If the factory that made this particular machine did not offer a steady, you'll just have to make your own.


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## tylernt (Apr 23, 2012)

350xfire said:


> You will find that you will quickly outgrow the 9x machine...


Why? He's probably not making prop shafts for ocean liners.  Assuming he's not opening a professional machine shop, even a 7x will probably be all he ever needs to make and modify flashlights. 



> As for steady rest, those make contact on the piece so they will cause scratches.


Hence masking tape and roller bearings.


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## vestureofblood (Apr 23, 2012)

tylernt said:


> Yep it sounds like that should work. On the left side there should either be levers where you can change the thread pitch, or, a set of change gears. If this machine uses change gears, make sure the machine comes with the rest of the set of gears! If they are missing, obtaining replacements will be a real hassle.
> 
> Steadies are generally specific to one make and model of lathe. Lathe bed dimensions are just to different to allow for a universal fit. If the factory that made this particular machine did not offer a steady, you'll just have to make your own.



I'm guessing thats what these are?




EDIT: I have no clue why that image wont resize.


It also comes with these.







Would it be easier to accomplish the task using he Grizzly is the G4000 9x19? To me a set of levers to do this sounds better. That 3 in 1 is out of production and if the gear size I need is missing that could be a problem. Also there is a Grizzly store where I live and getting a steady would probly not be hard.


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## tylernt (Apr 23, 2012)

In the red box? I can't really tell from the pic. If the red box contains gears of various sizes then those should be the change gears.

If you're not in the mood to make a steady rest, then you probably want the Grizzly lathe instead. Check out the steady that Grizzly sells for it, to make sure it opens up big enough to accept a D Mag.


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## precisionworks (Apr 24, 2012)

> will it be possible to get a steady rest for this machine???


Plenty of no-name (maker unknown) steadies on eBay. Buy one a little too tall & cut it down to fit.

The issue with any steady is that they rely on hard contact to work. No matter what is on the tips the part will get scratched or at least burnished. If you plan to work on larger tube lights it's worth the money to buy a lathe with a chuck big enough to do the job. I don't work on any lights larger than 18650/CR123 size, about 1" (25.4mm) body diameter. But the light is held in a custom machined fixture that's 2" (50.8mm) diameter & that requires a good sized chuck. 






A lot of lights & light parts are machined using a 5C collet chuck. I much prefer the 5C to a jawed chuck because the 5C has no jaws & it will not draw blood. Shown below holding a SWM V10R for body grooving:






The 5C chuck opens up all sorts of possibilities for work holding, like the internal expanding collet shown below holding a SWM extender tube:








You will never regret buying a bigger machine.


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## tylernt (Apr 24, 2012)

precisionworks said:


> The issue with any steady is that they rely on hard contact to work. No matter what is on the tips the part will get scratched or at least burnished.


Hence masking tape and roller bearings.


> You will never regret buying a bigger machine.


True.


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## precisionworks (Apr 24, 2012)

tylernt said:


> Hence masking tape and roller bearings.


 Just for fun take a piece of plastic pipe & wrap it with a few layers of masking tape. Hold that against a rotating wire wheel. That is exactly how long masking tape will last when run against a steady rest of any type.


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## vestureofblood (Apr 27, 2012)

UPDATE:





WOOHOO!


I decided to go with the grizzly, and I'm happy that I did. I got it at an estate sale from a retired engineer. The guy was a man after my own heart, everything was neat and well kept, all the parts are there. 

The price on it was $750 ( which was really a stretch for me), but this gave me the opportunity to get a lathe larger than I could afford new. THe seller said he would let me come see it before the sale, but if I wanted it before the doors opened I had to pay the full price. I wasn't taking a chance on letting this get away. 

The cabinet that it sits on came with it too. At the Grizzly store that cabinet is a laughable $225 Bucks! I got that and some other extras thrown in with it ( some small tools and a welding helmet).


I just wanted to shout out a super thanks to all of you who participated in this thread. You guys really had my back on this one.:thumbsup:


So far I have not been able to locate any classes in my area for machining ( even in the collage town 50 miles from here), so it looks like a lot of reading and some youtube are gonna have to do the job for now.

That said I may be back to this thread for some help 

Thanks again all.


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## StrikerDown (Apr 27, 2012)

Congrats! It looks almost new!


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## vestureofblood (Apr 27, 2012)

Yeah, the guy took good care of it.


Can someone please recommend me some bits? A set perpaps? I know for sure that I at least need the one that will be used to cut the threads on a D mag. Also I'd like to have the one mentioned earlier for separating pieces. For example when I make some heat sinks and I want to cut off the end piece.

Thanks


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## precisionworks (Apr 27, 2012)

http://www.mesatool.com/index.php?main_page=index&cPath=0

http://latheinserts.com/category.sc...59DAE822DA31D673F6.qscstrfrnt05?categoryId=82


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## 350xfire (Apr 27, 2012)

Congrats... That's a nice, well-cared for lathe! You won't regret going with that instead of the combo unit... You can start off with one of those 5 pc China-made tool sets from Ebay for about $30 and work your away up. That's what I use most of the time on aluminum.

Oh, and first things first, get a QCTP!


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## tylernt (Apr 27, 2012)

As for tools...

Some machinists prefer carbide inserts. In a for-hire machine shop where time is money, these make sense since you don't spend any time sharpening them and they have faster metal removal rates. 

Some home shop machinists prefer HSS. These come as blanks and you shape them on a bench grinder to whatever form you want. You don't run them as fast (but still plenty fast, 1,500 RPM for 1" diameter aluminum), but some users claim to get superior surface finish with HSS. Many also consider HSS to be cheaper, a HSS bit costs about as much as a carbide insert but the HSS can be sharpened indefinitely whereas the insert is thrown away after the edges are dull.

Myself, I primarily use HSS. I do have some brazed carbide I'll use for turning high-carbon steel but otherwise I've been very pleased with HSS.


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## precisionworks (Apr 27, 2012)

> You don't run them as fast (but still plenty fast, 1,500 RPM for 1" diameter aluminum), but some users claim to get superior surface finish with HSS.



All my twist drills are HSS & run at glacial speeds ... you can see them turning if you watch closely :nana: 

For machining mild steel on the lathe figure 100 sfpm for HSS, 400 sfpm for coated carbide inserts. 

In aluminum the HSS tool runs at 400 sfpm while the coated carbide inserts coast along at 1200-1600 sfpm.

It really depends on your level of patience. If you have lots of time to learn to sharpen tooling (& lots of time to machine the part) the HSS tools work well. If you get more enjoyment out of using a flashlight than you do machining it you'll want to consider inserts.


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## tylernt (Apr 27, 2012)

precisionworks said:


> In aluminum the HSS tool runs at 400 sfpm


Which is fast enough for me thank you very much. If I engaged power feed at 1200sfpm I'd crash into the chuck before I could throw the half nuts off!


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## las3r (Apr 27, 2012)

It's a nice lathe I just got one not to long ago 
http://www.candlepowerforums.com/vb/showthread.php?336576-My-new-Lathe
And just receiving my tools for it.....


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## StrikerDown (Apr 27, 2012)

I have a feeling Barry was referring to general machining ops not cutting threads specifically. I tend to cut threads on the slowest speed available for the reasons you mentioned. 

Carbide inserts are available on eBay quite often for MUCH less than suggested retail, It's not worth my time to grind HSS tooling except for those rare special form cuts.


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## precisionworks (Apr 27, 2012)

StrikerDown said:


> I have a feeling Barry was referring to general machining ops not cutting threads specifically. I tend to cut threads on the slowest speed available for the reasons you mentioned. .


+1

Most threading is done either slowly, very slowly, or really slowly depending on the width of the runout groove. General machining is done at whatever speed the insert manufacturer suggests, lacking that Machinery's Handbook has tables that address every machinable material regarding sfpm. With inserts the highest useful speed is the one that produces a tan colored curl that drops blue. With HSS the desired color is that of the parent metal.



> Carbide inserts are available on eBay quite often for MUCH less than suggested retail, It's not worth my time to grind HSS tooling except for those rare special form cuts


+1 again 

It's hard to beat a dollar or two to get four edges that last a long time. I ran AISI 1045 all day today, making flanges that are 6" (about 155mm) in diameter. Tan chips that dropped blue all day long & only one or two stuck to the side on my neck & left a mark :devil:

Ran through a total of eight edges ( 2 negative inserts) at a cost of under five dollars. Only enriched unobtanium tooling is less expensive.

If you'd like to read a really good article on machining low/medium/high carbon steels here's one from Cutting Tool Engineering magazine.


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## vestureofblood (Apr 28, 2012)

Ok, I have a somewhat serious issue here. I cant get the half nut lever to engage at all. I have the feed selector disengaged, and the thread dial moved in. With the machine on (or off) the HN lever will NOT engage. 

Is there some other thing I am suppose to do?


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## gadget_lover (Apr 28, 2012)

I know of nothing special to engage the half nuts. My 9x20 takes a little more force than my 7x12 does to get past the detent on the cam. It's quite a bit of force (several pounds) and is more force than is used on most of the lathe.

If the lathe is not running, I need to move the carriage slightly so that he teeth of the halfnut will align. If it's running (leadscrew turning) the teeth align instantly.

The feeling is... some force needed to start rotating the lever (clockwise) then it rotates a bit till the teeth hit the crests of the thread then another bit of movement as they mesh.

Is the lever moving at all?

Daniel


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## vestureofblood (Apr 28, 2012)

No I cant get it to budge. I have pressed about as hard as you would want to on a small lever like that. It feels as stiff as if feed lever was us ( even when its not) and the lock out was in place.


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## darkzero (Apr 28, 2012)

The HN lever should have a set screw that adjusts a ball & spring for the detent. Just thinking that it might have been tightened all the way in (which it's not supposed to be) or someone might have lost the spring & ball in there & just tightened it down. Try loosening it & see what happens.


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## gadget_lover (Apr 28, 2012)

If you can't find the product manual, this should be close. 
http://manuals.harborfreight.com/manuals/45000-45999/45861.pdf

[ deleted incorrect information ]

Daniel


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## darkzero (Apr 28, 2012)

gadget_lover said:


> The setscrew for my detent adjust is on the right side of the apron behind/below the threading dial.



To clarify, I guess we are talking about two different things. What I call the detent adjusts the stiffness/tension of the actual HN lever which is the setscrew, spring, & ball that is on the HF lever. The lever clicks into place when the lever is disengaged & enagaged. If the setscrew is tightened all the way down, then the lever may not be able to be moved at all. If the setscrew, spring, & ball are completely loose or removed, the lever would sag & not say in the disengaged (up) position. It would also move very freely & you would not feel it click into position.

On the side of the apron between the threading dial are two or three setscrews with nuts for locking to adjust the play of the actual halfnuts which do not have springs & balls. Unless they are completely out of adjustment, I don't think these setscrews would have anything to do with the HN lever being stuck. 

Also, since this Grizzly has a power feed lever, the feed lever must be fully disengagaed to engage the HN lever. On side note, since there is no power feed bar & only a leadscrew, what is the difference between using the power feed lever & HN lever?

In the G4000 manual, on page 39, fig 54 you can see the detent on the HN lever & page 53, fig 89 you can see the two HN adjustment setscrews. Not sure if the HF 9x19 is different. Both my 8x14 & 12x36 have the detent adjustment on the HN lever as they are basically the same design anyway.


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## gadget_lover (Apr 28, 2012)

As Will pointed out, the detent adjustment is that little allen screw in the halfnut handle.


The dimples that the ball goes into is hidden under the handle.

( I like the Grizzly manual better.  )

Daniel


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## gadget_lover (Apr 28, 2012)

darkzero said:


> Also, since this Grizzly has a power feed lever, the feed lever must be fully disengagaed to engage the HN lever. On side note, since there is no power feed bar & only a leadscrew, what is the difference between using the power feed lever & HN lever?



The power feed adds an extra set of gears to further step down the speed ( as slow as .0047 per rev with default gears) . The half-nuts run directly off the 16 tpi lead screw ( finest is .0178 pre rev , or 56 tpi with standard gear set) 

Daniel


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## darkzero (Apr 28, 2012)

gadget_lover said:


> The power feed adds an extra set of gears to further step down the speed ( as slow as .0047 per rev with default gears) . The half-nuts run directly off the 16 tpi lead screw ( finest is .0178 pre rev , or 56 tpi with standard gear set)
> 
> Daniel



I see, thanks. So there is an additional lever for the gearbox that is used to switch between threading & power feeding?


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## gadget_lover (Apr 28, 2012)

Both the power feed and the threading functions run off the leadscrew. A slot runs the length of the leadscrew. A worm gear mounted in the carriage has a key that runs off that slot. This worm is engaged when the lever is moved.

You select the leadscrew speed using the gearbox. This gives a faster power feed for roughing and a slower for finishing. 

Daniel


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## darkzero (Apr 29, 2012)

gadget_lover said:


> A slot runs the length of the leadscrew.



Now it makes sense. Didn't expect the leadscrew to have the slot on it.


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## gadget_lover (Apr 29, 2012)

darkzero said:


> Now it makes sense. Didn't expect the leadscrew to have the slot on it.



It took me a while to figure out how that worked. The worm gear is attached to the carriage and 'floats' on the lead screw. The key in the worm gear meshes with the leadscrew so it is turned by it. A gear is pushed into mesh with the worm gear and the hand-wheel gear when you raise the feed lever. 

Mine has an interlock that keeps the half nuts and power feed from engaging at the same time.

Daniel


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## BVH (Apr 29, 2012)

Although a different machine, my PM1236 has the same type of interlock and it is very surprising how very little movement it take on the half nut lever to lock out the power feed lever. If there were thousandths marks on the half nut lever, it would probably be 1/4 of one the distances between any two marks. I literally can almost not see the movement.


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## vestureofblood (May 1, 2012)

Ok, I got the half nut lever fixed.

I ended up having to take the assembly apart, but the good news is that it was just reeeealy stuck. A few taps with a hammer inside and some lube and I am back in business. 

I am still a bit unclear about cutting the inside threads on a mag. I understand setting up the gears, and when to engage the half nut, but which bit to use and the best way to get it in there are still a bit grey.

I think I may need a different tool holder, because mine only holds the bits at a 45 degree angle and the head of it is pretty big. Not only that its bent ,but I dont even know if thats how it should be.





Uploaded with ImageShack.us


I realize that I cant learn every thing I need to know about this from CPF, but I very much appreciate all the help you guys have to offer.


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## 350xfire (May 1, 2012)

You need an inside threading tool. Looks like a boring bar with a 60 degree (or whatever) insert. You can get the Mesa tools set. A bar that flips around and can do both inside and outside. Usually the bits will do a range of TPIs but there are specific thread bits as well. That's all I know- any more and I'd probably be lying (if I am not already!). I bought a geared lathe so I wouldn't have to hassle with changing gears. Once you get to making threads you'll want that...

http://www.mesatool.com/index.php?main_page=index&cPath=4


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## precisionworks (May 1, 2012)

> I bought a geared lathe so I wouldn't have to hassle with changing gears.


Many gear heads including mine come with a set of change gears. Not many lathes will cut both SAE & Metric without changing gears. My South Bend was belt driven & had all the gearing built into the transmission - but would not cut metric without additional gears.


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## 350xfire (May 1, 2012)

Yes, true! That's why I only do SAE... However, some day I may need to and I'll have to get a second lathe just so I can do metric threads. lol


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## gadget_lover (May 1, 2012)

There are "sharp V" tools, partial profile and full profile. 

The sharp V is the most versatile, but does not make a perfect thread. This is not an issue for tailcaps. A single tool will cut just about all threads.

The partial profile will cut a better thread, and will cut a range of 5 to 10 or so threads. 

A full profile will cut only one size thread but it will be the exact shape for that thread. 

When you cut inside threads you run the lathe in the normal direction. The halfnuts move the tool from right to left. The tool cuts the inside of the bore CLOSEST to you. The cutting edge is right at the center height or a few thousandths above.

As an alternative to the threading tool that uses inserts you can also get solid bars that are for cutting threads. Micro-100 is a popular brand. They are like boring bars that are shaped to match the thread.
http://d2n4wb9orp1vta.cloudfront.net/resources/images/cdn/cms/0411_PMTS_scientificcuttingtools.jpg

You can also grind your own from a HSS bit (square or round). 

 


Daniel


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## gadget_lover (May 1, 2012)

Your 9x20 (or 9x19) should be able to do metric threads. There is a 127 tooth gear in the compartment on the left.  The 127 and 120 tooth gears together give you the inch to metric ratio. Use just the 120T gear for imperial. 


Daniel


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## darkzero (May 2, 2012)

Is it true that most low to mid end imperial lathes that can cut metric threads with the change of some gears, the threading dial is completely useless for cutting metric threads?


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## tylernt (May 2, 2012)

darkzero said:


> Is it true that most low to mid end imperial lathes that can cut metric threads with the change of some gears, the threading dial is completely useless for cutting metric threads?


If you have an imperial leadscrew and wish to cut metric threads, or vice versa, do not use the threading dial. Simply leave the halfnuts engaged and reverse the spindle to move back to the beginning of the cut. If your spindle has no reverse, turning it backwards by hand will get old fast.


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## darkzero (May 2, 2012)

tylernt said:


> Simply leave the halfnuts engaged and reverse the spindle to move back to the beginning of the cut.



That's how I learned to thread on an old lathe that was missing the threading dial. I hated it. I was afraid that would be true and if there's no way around it I guess I will avoid cutting metric threads as much as I can.


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## precisionworks (May 2, 2012)

For standard internal threads a threading tap beats single pointing for the smaller sizes (3/4" or 19mm are the biggest taps I have). Drill the hole, chuck up the tap, set the spindle to around 50 rpm & the part is done in under fifteen minutes, cleanup included. 

For single pointing the gears on my machine are swapped out, meaning either 2 or 3 gear changes. Twenty minutes is average, thirty minutes if a screw is dropped into the pile of chips & oil on the floor. Add another twenty minutes to cut the thread. 

A few taps are pretty nice to have.


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## vestureofblood (May 10, 2012)

Precisionworks did you get my email?


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## precisionworks (May 10, 2012)

Nothing in the in box


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## vestureofblood (May 10, 2012)

Oh, ok, I'm not really sure what happened, but since CPF is back I can just post here. 

Basically what happened is this. I was practicing on my lathe doing the D mag threads and I got a few done and I noticed that they were getting inconsistent. At first I just figured I was doing it wrong, but then it quit all together. When I took the machine apart I found that all the threads on my half nut were stripped out. At first I figured this was probly my fault, but looking at it I see they are made from a thin cheap pot metal. I tried to get a replacement from grizzly and they are on back order til June 18 ( I guess others are having the same problem.)

What I am wandering is if its possible to have you make me a replacement ( out of something better perhaps)? If this is a realistic idea what do you think the cost would be? 

My email is vesture_of_blood(@)hotmail.com if you prefer that vs forum.

Thanks


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## precisionworks (May 10, 2012)

I'm way behind on both lights & industrial work but making half nuts isn't too hard. Find a long brass nut (barrel nut) whose threads match the lead screw. Split the barrel nut. Figure out how the old half nut was attached & attach the new one in the same way. 

The holy grail in acme screws & nuts is Roton Products.


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## vestureofblood (May 12, 2012)

Ok, its "tool time".

Here is the list I have compiled of things I think I am going to need. I'd like to get this right the first time so I am open to suggestions.

1. Indicating dial ( I think I'm just going to go with a cheap $30 one from ebay on this)
2. Thread center guage
3. Thread guages
4. New set of calipers my cheap set has out lived its usefulness so I am looking for recommendations on a better set.
5. At some point I would like to start boring C mags to fit 26650s so a boring bar.
6. Bit holder? I was able to get in the D mag to cut threads with the one I have ( it uses standard 1/4" bits) but just barely. So if I could buy one tool that could do both??


EDIT: Do you guys cut dry or with oil, do I need different oil for aluminum than for steel?

Thanks again all.


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## gadget_lover (May 12, 2012)

The D mag has a 20 tpi thread, so I'd buy a dedicated internal thread tool just for that. They look much like the one I posted earlier.

I use Tap Magic Gold for aluminum, Dark oil with sulfur for steel.

Your tool that holds the 1/4 inch bit at an angle appears to be for boring.

Daniel


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## vestureofblood (May 15, 2012)

Am I suppose to sharpen carbide bits before using them? I'm just wandering because I got a pile of them the other day, and they dont seem to work very well. If you run your finger over the edge they dont "feel" sharp at all ( you couldn't cut a hot dog with them), and to seem to leave as smooth of a surface on the metal. Comparatively I have a single HSS bit that seems to go through the aluminum like butter and leave a better surface.


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## precisionworks (May 15, 2012)

> if its possible to have you make me a replacement ( out of something better perhaps)? If this is a realistic idea what do you think the cost would be?



Did you contact Roton about a replacement? Their prices are a bargain compared to any other option.

In the unusual event that Roton has no nut that will interchange you may want to consider purchasing a mill. You can buy a pretty nice mill/drill for about what two nuts would cost to make.


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## gadget_lover (May 15, 2012)

vestureofblood said:


> Am I suppose to sharpen carbide bits before using them? I'm just wandering because I got a pile of them the other day, and they dont seem to work very well. If you run your finger over the edge they dont "feel" sharp at all ( you couldn't cut a hot dog with them), and to seem to leave as smooth of a surface on the metal. Comparatively I have a single HSS bit that seems to go through the aluminum like butter and leave a better surface.



If they are inserts, they should be ready to go. That's the beauty of inserts, you can swap them and have the same cutting edge you had before.

If they are brazed, then you you will probably need to touch up the edges. I find the cheap diamond coated disks in a dremel work fine for getting a sharp ( relatively sharp ) edge.

Daniel


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## vestureofblood (May 16, 2012)

precisionworks said:


> Did you contact Roton about a replacement? Their prices are a bargain compared to any other option.
> 
> In the unusual event that Roton has no nut that will interchange you may want to consider purchasing a mill. You can buy a pretty nice mill/drill for about what two nuts would cost to make.



I looked over the website, but I couldn't find any 9/16" acme/barrel nuts at all. By "contact" do you mean they may have stock not listed? 

I'm not sure weather to be encourage or discouraged about that mill thing, since I'm guessing you mean having a half nut made would cost like $300. LOL!

On a side note I did pick up the threading tool you mentioned. 
http://www.mesatool.com/threading-tools/1/2-threading/grooving-tool/
I like the fact that it can be used left or right. Those tips look like there going to make a lot smoother thread too.

I also grabbed a set of thread gauges, a center gauge, and a dial indicator with a magnetic base this week. Still weighing my options on the boring bar.


gadget_lover said:


> If they are inserts, they should be ready to go. That's the beauty of inserts, you can swap them and have the same cutting edge you had before.
> 
> If they are brazed, then you you will probably need to touch up the edges. I find the cheap diamond coated disks in a dremel work fine for getting a sharp ( relatively sharp ) edge.
> 
> Daniel



I guess that must be the deal then. Mine are the brazed. Back to the hardware store


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## precisionworks (May 17, 2012)

> I looked over the website, but I couldn't find any 9/16" acme/barrel nuts at all. By "contact" do you mean they may have stock not listed?


I'd call them on the phone. 9/16" is not an uncommon size for a company that specializes in these items.


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## vestureofblood (May 18, 2012)

I guess I could use a little help with something else now too. I cant seem to get as smooth of a finish on my parts as what I have seen others get. 

I picked up some HSS to use for bits while I look into the diamond wheel thing for the carbides. I made a bit like this as best I could, the angles may not be identical but the edges are straight and the bit is sharp.

I centered the bit within probly less than 1/16", and squared it as best I could. I set the lathe chuck speed as high as I could get it and the carriage speed as low as I could figure out how to get. 

I picked up some cutting oil ( cheap ace hardware tapping oil) and am using that, and made sure my setup is rock solid, cross feed etc is down tight. But the finish on my part still looks like a ring shank nail. It doesnt feel that bad, but I know it can be way better than this.







The chips seem to be coming off in long curly cues, and I am only removing about .002 at a time.






Here is a video so you can get an idea of the speed ratio.

http://youtu.be/FrEBhuO51E4

Any ideas would be helpful?


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## precisionworks (May 18, 2012)

Depth of cut should be at least equal to nose radius.


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## gadget_lover (May 18, 2012)

It helps to know what you are trying to turn. 6061 Aluminum? Cold rolled steel from Ace hardware? 12L14 steel? Some metal just does not cut well. 

The cutting edge can't be just close. It really needs to be right on center. There are many ways to do that. I often use the 'pinch a feeler gage trick'. See here:
http://madmodder.net/index.php?topic=1661.0

You have to move the carriage slowly to get a good finish. If you have a sharp tip (not rounded) and move the tool too rapidly you will end up with surface that is ridged. Your video looks about right for a roughing pass. It's two or three times faster than I do a finishing pass.

Daniel


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## vestureofblood (May 19, 2012)

precisionworks said:


> Depth of cut should be at least equal to nose radius.



This helps. I started taking deeper cuts and just moving the carriage by hand so its slower, I also re cut the bit so that there is less of a radius at the tip.



gadget_lover said:


> It helps to know what you are trying to turn. 6061 Aluminum? Cold rolled steel from Ace hardware? 12L14 steel? Some metal just does not cut well.
> 
> The cutting edge can't be just close. It really needs to be right on center. There are many ways to do that. I often use the 'pinch a feeler gage trick'. See here:
> http://madmodder.net/index.php?topic=1661.0
> ...



My bad, I am using aluminum but I dont know the grade. Probly what ever is cheap since I didnt specify at the supplier. 

I also slipped a shim made of flashing under my tool post so that I now have dead center.

These things combined have given me a much better finish. Still not as good as the pros, but 30 seconds worth of sand paper at the end completes the task well enough for now  

Thanks again guys.


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## precisionworks (May 20, 2012)

The inexpensive brazed tools from China are made of repro (reprocessed) carbide. Repro consists of varying percentages of C1 C2 C3 C4 C5 & C6. The most interesting feature of repro is that no two batches are ever identical because the processor buys worn out inserts by the drum full, grinds the old inserts into powder & makes "new" carbide. New being a relative term. FWIW inexpensive inserts also use repro with the same results. 

Since many inserts cost about $2 on eBay & a holder costs $25 there isn't much reason not to use inserts. They will save you hours & hours of time & each edge is identical to every other. You'll never be able to sharpen a brazed tool the same way it was last sharpened unless it's sent out to a sharpening service.


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## vestureofblood (May 21, 2012)

Yeah, I'm thinking I'll just cut my losses at the $25 mark on those brazed ones. I only bought them because I thought they were ready to go out of the box.


I did pick up the tool specifically for threading that uses inserts you mentioned. I was thinking about getting a boring bar from the same place. I saw they have a turning tool and also one that says its a combo.
http://www.mesatool.com/boring-bars/1/2-turn-boring-tool/

With the combo tool do I just need a different insert for boring? Or should I just get a boring bar for boring and a turning tool for turning?


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## gadget_lover (May 21, 2012)

You are not losing anything on the brazed carbide. 

They are still useful for roughing and many other tasks. They are easy to shape with appropriate wheels. Do you have a dremel? I use these; http://www.harborfreight.com/5-piece-diamond-mini-cutting-discs-31501.html and also http://www.harborfreight.com/4-piece-large-diamond-grinding-wheel-set-32397.html .

I also have normal sized grinders, but these are real convenient. 

Daniel


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## vestureofblood (May 21, 2012)

I do have a dremel. I think since I do have the brazed I may pick up that a set of the diamond wheels. I may get them tomorrow at HF since I have to go all the way to Springfield any way. I'm gonna have to pick up a new steady rest with the barrings ( and cut it down) at Grizzly.

I still want to get one of the insert type boring tools, once I figure out what I need to buy and which inserts etc. I used that threading one today and I like how it works.


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## darkzero (May 22, 2012)

I only have very few brazed carbide bits but they are all Seco or Micro100. Never had any issues with them & I've never even sharpened them yet because of how often I use them. They're inexpensive so I don't even bother buying the cheap import stuff.


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## precisionworks (May 22, 2012)

darkzero said:


> they are all Seco or Micro100. Never had any issues with them


Those are made from virgin micrograin carbide. No way to compare Seco or Micro 100 with repro.


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## vestureofblood (May 24, 2012)

I went ahead and picked up the 1/2" boring bar from mesa too. How do I know what inserts will fit my boring bar and threading tool?


EDIT: I figured out a gear ratio on my lathe that will give 20 TPI without use of the halfnut ( while I work that situation out I can still practice), but the issue I seem to be having now is the angle of the threads. When I cut an outside thread on a mag for making an extension by the time the threads have a sharp enough peek on them the metal is too thin and breaks off. How can I change the angle of the threads?? Do I need a different bit with a wider angle or can I change something about my approach?


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## 350xfire (May 24, 2012)

vestureofblood said:


> I went ahead and picked up the 1/2" boring bar from mesa too. How do I know what inserts will fit my boring bar and threading tool?



That is a science all to itself... I have asked that question before and not sure I really understood. I usualy just order a few inserts to make sure I don't have to deal with it. I would just ask MESA.


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## gadget_lover (May 25, 2012)

vestureofblood said:


> When I cut an outside thread on a mag for making an extension by the time the threads have a sharp enough peek on them the metal is too thin and breaks off. How can I change the angle of the threads?? Do I need a different bit with a wider angle or can I change something about my approach?




You need to read up on threads. The "standard" thread is 60 degrees and has a FLAT top and a FLAT bottom with slightly rounded edges. It does NOT have sharp peaks. The threading tool has a 60 degree profile and, depending on the design, a flat tip. 

You want to read up on the Unified Thread Standard (UTS).  Wiki article on UTS

It only looks complicated. It's not really.

I forgot... Why can't you use the halfnuts?

Dan


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## gadget_lover (May 25, 2012)

Repeat deleted.


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## vestureofblood (Jun 23, 2012)

gadget_lover said:


> I forgot... Why can't you use the halfnuts?



They were stripped out. I have since got a new set. They are made of the same low quality aluminum pot metal. Also the replacement part was a poor fit ( the whole unit was 10% smaller than the original) so hours of work to get that going, but its done now.


I have also made some other upgrades to the lathe. I made a steady rest by taking the bottom of the factory one and the top of another and making one usable tool out of 2.









Also another even better upgrade was to a full size AXA QCTP. When I first saw the factory Griz tool post I sort of liked it because I thought it looked versatile. After having used it I dont even know why posts like that are still in production. 






Going to a better tool post increased the lathe rigidity by about 3-400%. This in combination with a few other changes ( to my technique) have given very nice results. 


This next pic I am going to show is just so that if any noobs ( like me  ) come and visit this thread and would like to upgrade to an AXA QCTP here is how I decided to do it.

All that I did was get a grade 8 bolt from lowes ( get a size bigger than you think you need so you have plenty to chuck) and made a new bolt to extend out of the compound. Then I cut off the bolt that came with the new post and threaded the inside of it. This way the thread on the bolt I made and the inside of the existing one were of my choice standard thread and not some obscure metric since a tap was needed.

Also doing it like this there is no mod needed to the lathe or to the actual tool post.







This week am am looking into buying a band saw, so if any of you have tips on what to buy or something you wish you did not I'd be glad to hear it. I know I want to go with probly at least a 12" saw.


Thanks again every one for your help.


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## las3r (Jun 23, 2012)

vestureofblood if or when u learn how to do threads on that lathe let me no some tips on how to do them  I have the same lathe


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## vestureofblood (Jun 23, 2012)

I've got it going. Check out my sales thread in CPF. 

Watching Wquiles videos on doing it helped me. When I do them now I dont disengage the half nut at all, so the thread dial is unneeded. In the G4000 manual it suggests doing it this way. I guess they realized the part was defective and thought it would be cheaper to just write that in the manual then to change the design. 

There is a guy on youtube mrpete222 that has some very good vids on threading as well.

Getting the light body held rigid enough is the hardest part. I made adapters out of aluminum round stock that the bodies thread into that I hold in the chuck. I'll try to throw up some pics later.


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## precisionworks (Jun 24, 2012)

Nice job getting a working steady 

The steady that came with my lathe is a dead nuts copy of the South Bend 9 or 10 steady. The major diff is that the SB steady was ready to run & my Asian steady needed half a day at the PW Remanufacturing Center. First up was a complete remachine of the clamp shoe followed by fabricating a new hold down bolt:






The "before" images are so ugly that they cannot be shown on this forum. Finished by milling out the bottom of the shoe so the new bolt & bolt support were a nice sliding fit:






Now the steady could be clamped to the bed but it was still not ready to run. The lock screws that secure each finger in place were 4mm & did nothing to lock the fingers. Threw them into the scrap pile & drilled out the holes for 5/16-24 lock bolts & matching jam nuts. 






The square ends of the screws would not engage the narrow slots in the fingers so the ends were turned down to a dog point profile like the image below:






The diameter of the dog point was turned so that there is 0.1mm clearance on either side of the point.


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## vestureofblood (Aug 27, 2012)

Hey guys I have another question.

What is the best way to make a heat sink (say for a D mag) with a recess in it. Here is a picture of what I mean.





I want a sink that has "walls" that go up the sides of the mag head with a recess in the center for the light engine. 

I have done this a few ways but its not quite as perfect as I would like ( and really slow). What are your thoughts on the deal?


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## wquiles (Aug 27, 2012)

You can do all of that without having to take the piece out of the chuck:

1) Hold round stock in chuck, with enough extra so that you can later cut-off the part close to the chuck
2) Turn outside to the target OD side of the part farthest away from chuck's face (largest diameter)
3) Face part
4) Drill into part, and finish bore to final ID and depth
5) Turn outside to the smaller diameter the part closest to the chuck's face (depending on how stiff it is, you might be able to use parting tool for this - go slow)
6) Cut-off part for the right length

7) Optionally face the part of the heatsink that was just cut-off

Note you can do step #5 after step #2 if you like.

Will


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## vestureofblood (Aug 27, 2012)

Ok where I seem to be having some trouble is around step 4.

After the whole is drilled are you just coming into it several passes with a boring bar until the ID is correct? I did this but the problem I seem to have is the bottom face of the sink is not perfectly flat then. Are you doing some kind of a pass cross ways at the bottom once the ID is bored?


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## BVH (Aug 27, 2012)

vestureofblood said:


> Ok where I seem to be having some trouble is around step 4.
> 
> After the whole is drilled are you just coming into it several passes with a boring bar until the ID is correct? I did this but the problem I seem to have is the bottom face of the sink is not perfectly flat then. Are you doing some kind of a pass cross ways at the bottom once the ID is bored?



Same here - even using my DRO to always return into the same exact depth when making each boring pass. So It just hit me one day - Use the boring bar to "face" the bottom of the hole. Works great!


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## vestureofblood (Aug 28, 2012)

I think I may need to get a different style boring bar. I tried to do that with mine and it did help but I still got a pretty rough edge right a the corner.


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## wquiles (Aug 28, 2012)

BVH said:


> So It just hit me one day - Use the boring bar to "face" the bottom of the hole. Works great!


That is "exactly" the trick. But an additional trick is that depending on the intended diameter, for the initial hole I try to use a 0.5" milling cutter (4-flute, center cutting) to start the hole.




vestureofblood said:


> Ok where I seem to be having some trouble is around step 4.
> 
> After the whole is drilled are you just coming into it several passes with a boring bar until the ID is correct? I did this but the problem I seem to have is the bottom face of the sink is not perfectly flat then. Are you doing some kind of a pass cross ways at the bottom once the ID is bored?


Yes, the face is not flat after all of those boring passes. What is why you then use the boring bar to face the bottom of the part.

Lets say you are trying to hit a pocket depth of 0.350" and 0.600" diameter. You first drill the hole with a .500" milling bit/drill (or anything close to the .6") but don't go all of the way to 0.350" depth - you will be "cleaning" the internal face and finishing the surface on the face with the boring bar AFTER you have achieved the desired ID.

Basically you leave 0.002" to 0.003" from hitting the target depth, as you continue making passes on the ID to hit your target ID with the boring bar. When you hit your target ID with the boring bar, you then go all of the way to the final depth (0.350"), and then push the boring bar further in (while keeping the carriage locked - remember we are facing now), towards the center of the part - it will face the center of the part in that final operation, but it only works if you only have a few 0.001" left to cut since you are cutting "backwards" with the boring bar. Once the cutting tip reaches the center of the pocket, then retract the boring bar. Note that as with any facing operation, if the cutting edge in the boring bar is not perfectly centered, you might have a slight point/dimple in the middle of the pocket.

Will


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## vestureofblood (Aug 28, 2012)

Could you guys give me an example of what kind of boring bar/tip you would use for this. Even with mine at a slight angle I still seem to get some chatter across the bottom. This is what I am currently using.

http://www.mesatool.com/products/boring-bars/

Mine is the 1/2 by 6" and it has the same insert that is in the picture.


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## wquiles (Aug 28, 2012)

Chatter is caused by various things, but overhang is certainly one of the most important things. How much is the boring bar hanging outside of the holder?

Another significant factor is insert selection. If you are doing this machining on Al, it is best to have a very sharp insert, even better if it is an Al-specific insert (which also work fantastic on Delrin/acetal). Here is a previous thread of mine with such inserts:
http://www.candlepowerforums.com/vb/showthread.php?246303-Photos-of-inserts-for-Aluminum&highlight=


Will


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## gadget_lover (Aug 28, 2012)

That tool looks like the end is 90 degrees from the side. That would cause chatter, since a broad surface is in contact when you try to face the end of the bore.

If you used the tool that uses the dpgb insert at http://www.mesatool.com/products/turning-tools/ it should work better.

Daniel


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## wquiles (Aug 28, 2012)

gadget_lover said:


> That tool looks like the end is 90 degrees from the side. That would cause chatter, since a broad surface is in contact when you try to face the end of the bore.
> 
> If you used the tool that uses the dpgb insert at http://www.mesatool.com/products/turning-tools/ it should work better.
> 
> Daniel



+1

Excellent point about the shape/tip on the insert Daniel :thumbsup:


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## wquiles (Aug 28, 2012)

wquiles said:


> That is "exactly" the trick. But an additional trick is that depending on the intended diameter, for the initial hole I try to use a 0.5" milling cutter (4-flute, center cutting) to start the hole.
> 
> 
> 
> ...




By the way, it is not easy to appreciate the details, but in my website, on this page, on video #9, I am doing "exactly" what I described above. On the video, at about 5:50, I start the facing operation on the bottom of the cavity (in this case, this cavity is for the LED star):
scroll down to video #9


Then later on the same web page, on video 18, I am doing the same thing on the opposite side of the custom heatsink/pill (this other cavity holds the custom PWB LED driver & controller that I designed for this project), and about 7:50 you can see the internal facing operation:
scroll down to video #18

Will


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## vestureofblood (Sep 19, 2012)

Ok, here is the next plan.

What is the best way to get a perfectly flat bottom in small work? I have some 5/8 brass rod and I need to bore holes into it that are flat on the bottom. I was able to do this ok with a self cut HSS bit when the holds I needed were less than 1/4" deep but now that I need some bigger thats not doing the job.

I thought maybe I could use an end mill but I am wandering if that is going to leave a nipple in the center? An LED will sit at the bottom of this hole. Also if I did get an end mill what do I need? 4 flute? Is there anything else about them I need to know?


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## BVH (Sep 19, 2012)

I use center cut endmills for making small diameter flat bottom holes.


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## moderator007 (Sep 19, 2012)

BVH said:


> I use center cut endmills for making small diameter flat bottom holes.



+1
I use the same.


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## vestureofblood (Sep 19, 2012)

Ok so then like this?

In the picture it shows one with a big hole in the center, but I am guessing that is not what the actual bit looks like correct?

Also is this going to be made from the same HSS like what the blanks I use for making bits are? The reason I ask is because I have to reduce the shank size to fit the little baby chuck in my tail stock. I have some other bits that I am guessing are an alloy of some kind, or possibly cobalt, and reducing the shank on those didnt go well for me ( didnt go at all really).

EDIT: I would really prefer to have a 13/32 than a 10 mm ( closer to the perfect size) but I cant find a HHS 4 flute one will a 2 flute leave a smooth enough surface on the bottom for the LED?


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## BVH (Sep 19, 2012)

The description reads correctly but the pic sure makes it look like there is no center cutting material in the center. Probably just a pic issue. As long as it is a center cutting endmill, it will do the trick.


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## wquiles (Sep 19, 2012)

BVH said:


> I use center cut endmills for making small diameter flat bottom holes.



I do as well, but then use a boring bar to make the bottom of the hole truly flat. In my experience, the "center cutting" mills don't quite give me a truly flat bottom. True, for most stuff it is irrelevant, but if the pocket/hole is for an LED or an LED Star, then you do want a very "flat" surface so that you get more optimum heat transfer when using thermal paste/epoxy.

Will


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## Th232 (Sep 19, 2012)

wquiles said:


> I do as well, but then use a boring bar to make the bottom of the hole truly flat. In my experience, the "center cutting" mills don't quite give me a truly flat bottom. True, for most stuff it is irrelevant, but if the pocket/hole is for an LED or an LED Star, then you do want a very "flat" surface so that you get more optimum heat transfer when using thermal paste/epoxy.
> 
> Will



Ditto. I've found that with a lot of centre-cutting endmills the centre is slightly higher than the edge. You can test this on a piece of scrap that you've faced, slowly feed the endmill in and see if a ring appears first. That's been the case for pretty much all the endmills I've seen.


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## TexasLumens (Sep 19, 2012)

wquiles said:


> I do as well, but then use a boring bar to make the bottom of the hole truly flat. In my experience, the "center cutting" mills don't quite give me a truly flat bottom. True, for most stuff it is irrelevant, but if the pocket/hole is for an LED or an LED Star, then you do want a very "flat" surface so that you get more optimum heat transfer when using thermal paste/epoxy.
> 
> Will



You're exactly right Will. As well, it seems to me that the 4 flute end mills are a little worse about that than the 2 flute. I use only carbide tools so I don't know if its true in HSS or not but it sure is in carbide. 

Here is a boring bar I like for the small holes, this one will begin a bore in ... I think its .43" diameter. That front edge works perfect for flattening the bottom as you describe.




I am about to do the same thing on this little drop in I am working on... but I'm going to cheat and let the cnc mill do most if not all of the work then polish it out on the lathe. The mill will leave the bottom flat as your foot!! (Lazy)

The drawing isn't finished but you get the idea.


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## vestureofblood (Sep 19, 2012)

Where would I find a boring bar that will fit in a 10mm hole?


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## TexasLumens (Sep 19, 2012)

vestureofblood said:


> Where would I find a boring bar that will fit in a 10mm hole?



Look on Travers at Travers.com... 10 MM is .393XXX and they have a Micro100 part number 24-525-034 that will go in a minimum bore of .330. It's small and tender but I think anything in that size will be. It has just a .250" shank but if your careful you can get it done.


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## KC2IXE (Sep 23, 2012)

BVH said:


> I use center cut endmills for making small diameter flat bottom holes.



They don't actually leave "perfectly flat" bottoms in a hole - the center will be slightly higher than the outer edges (it's a degree or two). Depending on "how flat is perfectly flat" this MAY be 'good enough' (usually is) or may NOT be. If not, your oprions include actually circular milling the pocket (but usually won't leave a perfectly round hole) OR a facing type boring head, then you get a REALLY flat bottomed hole, starting to get to the limits of your machine. Want to go nuts, do it on a jig bore with say a flynn boring head, or other high end head


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