# my chuck got minor damage today :(



## wquiles (Jan 23, 2009)

I started working on the bomb-proof host project yesterday:
https://www.candlepowerforums.com/posts/2800759#post2800759

Today while working on the heatsink, just touching up the start of the threads, I got confused on the levers on the carriage and was not able to disengage the threading in time and it kept going and going towards the chuck!. Although I managed to turn off everything OFF, it did not occurred to me to use the foot brake, so while the spindle slowed down, boom ... 

Luckily I was touching up the beginning of the threading and I was going really slow (68 RPM or so). The thing is, I know better. I left myself no room and I was not even prepared to use the foot brake. I need to be more careful ... 














Will


----------



## SafetyBob (Jan 23, 2009)

Been there done that Will. That was a long, long time ago and it scared the crap out of me. 

Glad all you had was a little damage, could have been much worse and now you will always be reminded to be more careful, no respectful of the power of that lathe. 

Bob E.


----------



## SafetyBob (Jan 23, 2009)

If I am lucky, I will get to try that on my new 10" Bison 6 jaw that I have a day and a half to see if I will on eBay.....please cross you fingers for me. 

Mac will be proud of me. $371 + 50 shipping. Of course there is the problem with the backplate I would have to pay full price for at the usual places....

Bob E.


----------



## Mirage_Man (Jan 23, 2009)

Yikes! How'd that happen? You were cutting threads and you weren't able to dis-engage the half-nuts in time? When threading I usually engage the half nuts while the tool is at least an inch away from the part. That usually gives me plenty of time to put my right hand on the half nut lever and left on the cross slide wheel. I keep my hands there until I get where I want to stop threading. That's when I dis-engage the half nuts and roll out of the thread at exactly the same time.


----------



## KowShak (Jan 23, 2009)

The damage to the chuck doesn't look too bad, what collided with the chuck and how did it come off in the fight?


----------



## donn_ (Jan 23, 2009)

Did the Bomb-Proof Host survive the assault?


----------



## wquiles (Jan 23, 2009)

Well, it was very minor damage, but I felt pretty stupid last night :mecry:

Like Brian, I always have my hand on the half-nut lever, but for some idiotic reason, on the last pass, I simply did not have my hand on the half-nut level, and when I went to look for it, I think I grabbed the power feed level instead  - after that did not work (duh!) I hurried to turn the lathe off, but the big inertia meant the chuck had a few more turns before stopping, but it was too late 

Well, live and learn ...

As to the parts, not a perfect fit, but they worked out really well - I have to work some more on this over the weekend:











Will


----------



## MarNav1 (Jan 23, 2009)

Happens to us all. I'm just glad it was a chuck and not a finger or hand. Good luck.


----------



## Mirage_Man (Jan 23, 2009)

MARNAV1 said:


> Happens to us all. I'm just glad it was a chuck and not a finger or hand. Good luck.



LOL, yeah when I first got my South Bend you should have seen my knuckles :laughing:. It only took a couple of those to make me learn.


----------



## StrikerDown (Jan 23, 2009)

Just like the first scrath on a new car, it always sucks, I feel your pain! Glad your pain was only in your gut.

Does your new have seperate levers for threading feed and the half nut?

That seems like it would be confusing til you get used to it.

Does the foot brake shut down the electrical as well as stop the spindle?

Sorry for all the questions, but I am still undecided between getting your lathe and the Griz G4003G. Like you were! 

I think Grizzly is trying to help me decide, their Gunsmiths lathe went up $200 Jan 1st.


----------



## Anglepoise (Jan 23, 2009)

There is not a machinist alive that has not had a 'crash' of some sort at some past time.
Glad your hands are OK. And we all feel for you.


----------



## kromeke (Jan 23, 2009)

Bummer crash. I just had a student employee do the same thing to my "new" lathe at work. He thought I'd be pissed. I'm not, crashes sometimes happen to even the best of us. He was very apologetic. 

I don't need to tell you now, but that footbrake can be a really cool thing to have handy. I keep my foot on mine if I'm working close and towards the chuck. 

Sucks to have that happen to the hard jaws on your six jaw chuck. Looks like the damage is is a spot where it will seldom matter, but I'm not sure what kind of work you do. I know that I seldom hold rings or pipes on that step. 

Yes, any machinist worth his salt has had crashes. The better one have fewer, but I don't think you can claim to be a machinist without some minor crashes in your machining. 

At least the jaws are replaceable (at fair expense).


----------



## 65535 (Jan 23, 2009)

The only machining crash I ever had was a case of mistaken z travel which after drilling through some aluminum bar sent the bit even deeper into the piece then moved the x axis for the next hole with the bit all the way in the hole. Lost a bit but wasn't too bad.


----------



## Superdave (Jan 23, 2009)

I remember a guy in high school metal shop that walked away from the lathe, the bit hit the chuck and locked it up solid with a HUGE bang, the lathe survived but i think the instructor needed a new pair of pants. :naughty:


----------



## Mick (Jan 23, 2009)

Bison will sell you new top jaws. Been there! Mine fit perfectly.


----------



## wquiles (Jan 23, 2009)

Thanks much for the comments guys - much appreciated 

The damage affects a part of the jaw that I never use (at least not yet), so everything is still in working condition, so it is not something I have to fix/replace to continue working on my projects. 

I guess I better start saving for the buy-new-top-jaws-for-my-Bison foundation 

Will


----------



## kromeke (Jan 23, 2009)

Now for my constructive criticism:

If the picture is the setup, you have a poor setup. You left no room for your thread tool to exit. Or are you threading away from the chuck? In that case it was still control reversal, but you should have still given yourself more room. I assume you're working with insert tooling? Nice, rigid, and hard insert tooling? Gotta give yourself some room for error, this isn't CNC. It's your lathe, so I don't have to tell you how much you paid for it. 

I don't have a six jaw. Sometime I wish I did, so I'm envious. I do have a nice three jaw with hard top jaws. I can swap out the hard jaws for either soft jaws or pie jaws. I'd get some aluminum soft jaws and bore to the size needed. A collet setup might also be better, I've got a collet chuck and 5c collets. If your working over 1", you'd want something bigger than 5c. My ideal setup would be for a 5c with taper for a pot collet adapter. This is for rings and short work greater than 1", up to maybe 5". However, if your working with long lengths of tubing, a larger collet would be in order. A collet setup can still be a victim of operator error, but if you hit something it is usually at worst, a collet. Usually the tool looses, but it is all dependant on the nature of the collision. 

You have replaceable hard jaws, I haven't looked, but I assume that soft jaws are available for it. I don't know what tooling you have, you may already have a 3jaw with removable tops. 

Look into your options for workholding. I don't know the nature of your work, other than this part, but I assume you got the six jaw for tubing. I know it didn't come "extra" with the lathe. You can also always make custom one-off collets or collet like things and mandrels. I always have emergency 5c collets around for the odd jobs that come through the door. (emergency collet is a soft collet that is bored to the size needed.)

I looked at your thread regarding your new lathe. Nice looking machine. I think the one I have at work is in the same class. Mine is an MSC "Prince" lathe. I wish my spindle speed would go slower, yours does. Mine bottoms out at 105, threading gets a little hairy sometimes. It is a 13"x40

Nice chuck. I like Bison stuff.


----------



## Torque1st (Jan 23, 2009)

Just like Mick said; get yourself another set of jaws, no big deal. I second kromeke's thoughts. Always leave yourself some over travel room. Make a fixture if necessary.


----------



## wquiles (Jan 24, 2009)

Thanks guys 

I decided to give it another try today, but instead of using another heatsink and body, with the help from Daniel (Gadget_Lover), I decided to use a shallower thread than 20TPI, so I am trying 30TPI (having the levels to change threads right in front without having to change gears by hand is awesome!). 

The internal threading bit is narrower and can do the 30TPI fine, but the external bit I currently have (Kennametal TopNotch threading insert) only works from 8-20TPI, so the outer threads are not as "pretty" as if I had the right tip (I will order this week), but everything worked perfectly - it is the first time for me doing both sides of the thread, designed to match each other, but with Daniel's help it worked first time, without need to touch up anything!

Well, you know me by now. I have "some" pictures to back up my story ...

Here I am starting the "tube", same ID as the actual Barbo tube:





















Here I am threading the inside of the tube to 30TPI:











then I parted the piece:






I then took another piece of scrap and turned to be as the heatsink I will be using:






and this time, I am not only being extra careful, but I am also leaving myself LOTS of room. While doing this I also had the foot on the brake, just in case ...






note the threads are a little bit too thin at the crest - this due to having too big a cutter for the threads:






still, everything fit, first time, with no touch ups - Daniel would be proud 
















Now that I have practiced some more, I feel more confident moving to the actual hosts/heatsinks 

Will


----------



## gadget_lover (Jan 24, 2009)

wquiles said:


> Thanks guys
> 
> I decided to give it another try today, but instead of using another heatsink and body, with the help from Daniel (Gadget_Lover), I decided to use a shallower thread than 20TPI, so I am trying 30TPI (having the levels to change threads right in front without having to change gears by hand is awesome!).
> < snip >
> ...




Daniel IS proud!

Good work Will. Actually, I'm just glad that I did not give you bogus advice.

I am SO envious. 6 jaws, quick change gearbox , AND the luck to get the thread right on the first try! 



Daniel


----------



## precisionworks (Jan 24, 2009)

There are only two types of machinist - those that have crashed & those that will

A useful chuck mod is to bore the end of the jaws to hold thin parts, like washers or spacers. My South Bend has only one-piece hard jaws, so there's no soft jaw option. Mine are bored for a small OD part (a short piece of 1/2" drill rod was clamped in the jaws for a spacer), so anything larger than that has 6 point contact, which isn't perfect but still works OK. When this was posted on the PM forum, many members gave me Holy Hell for mucking up a "pristine" chuck. But, it works well.


*3 jaw chuck tip after boring*







*Holding a thin spacer with 6-point contact*


----------



## Anglepoise (Jan 24, 2009)

Will,
We all have our 'pet' procedures and as you get to know your new machine, you will adapt yours.

If the design specs allow it, I always try to machine a run out groove for the threading insert. Then the sound changes as the cutting tip arrives at the groove. You will probably notice that to disengage the half nuts, it take more pressure on the lever when actual cutting is going on. When it enters the groove,and cutting stops, disengagement is instant with no resistance.

Also IMHO,DRO is useless when threading. Of course it works, but most people find that watching a digital readout is not easy as the digits rapidly change.

I set up a 1" dial indicator, and watch the swing of its needle aproach Zero, to let me know when action on my part is required ( open half nuts, rewind cross slide, or whatever system you use to disengage )

Good luck, and thanks for sharing all this. Takes me back a few years...<g>


----------



## precisionworks (Jan 24, 2009)

> I set up a 1" dial indicator


+1

The best $10 you can spend is for a pair of mag-backs for two of your indicators:






(Little Machine Shop, P/N 2531)

If you want an indicator with mag back already attached, J&L often has them on sale for around $30:






Stick one where it will contact the carriage when it gets within range of the end-of-thread. Stick the other on the cross slide ... when the threading tip is retracted, you lose zero, and this indicator allows return to zero + your next depth of cut.

Useful for lots of other lathe work in addition to threading, like boring to a shoulder, or drilling to a desired depth.

FWIW, these indicators get beat to death. Hot chips, cutting oils, etc., are tough for them to handle. Mine look like they've been through World War III, with cracked lenses, melted spots, you name it. When one stops working (or starts to get sluggish), it goes in the trash. This is not the place for a nice Starrett or Mitu indicator


----------



## cmacclel (Jan 24, 2009)

Wow Will bigtime BUMMER!

Once I engage the threading lever my hand never leaves it. I crashed my Grizzly once as I tried cutting threads at the slowest speed and the threads looked somewhat torn as yours do. I then with the same piece chucked bumped the speed up to 200 rpm and when I engaged the threading lever to take another finish pass the threads did not line up in the same spot so I essentially was cutting threads in one pass. With that much load on the cutter I could not disengage the lever. I immediatlely hit the panic button and luckily I just broke the carbide tool.

Mac


----------



## kromeke (Jan 24, 2009)

I prefer to use the half nuts when I can, my hand also never leaves it while threading. However, on the lathe I use, which is a new lathe, the nuts don't seem to engage cleanly. So I've frequently use it with the half nuts always engaged, using the foot brake to stop it, and reversing the carriage. This is a little slower and not ideal, but you also have to use this technique when metric threading, which I've done on occasion. (I think there are a couple of lathes out there that use a dog-clutch to disengage the leadscrew and can metric thread with inch lead screws without reversing the carriage, Hardinge and Monarch come to mind)

I still plan to fully diagnose the issues I have with the half-nuts on this lathe here, but I haven't dived into it yet. 

Know the proper direction with the control lever. This is where I like having forward and reverse buttons, but the lathe here has a control lever that rides with the apron. For mine, down is forward, up reverse. Don't forget, hammer it into your brain. Engage brain before lever. 

On this new lathe, I've run the post into the workpiece (it was aluminum so just some grinding sound, no permanent scar. I've also power fed into the limits of the machine, once against a stop in the Z, once at the end of the cross slide throw. This lathe has a slip clutch on the feed rod, so it doesn't break anything. The post against the work was because I didn't look carefully at the job before applying power to the spindle. I was then looking at the cutting edge, not the toolpost an inch and a half behind it.


I usually spin the chuck by hand while in neutral to make sure my jaws clear everything when my carriage is all the way to the left, for a given cut. I've got a DRO on this one, it helps with a lot of things, but I don't pay attention to the Z while threading. I'm focused on the cutting edge while the half nuts are engaged. And the sound.


----------



## Alan B (Jan 24, 2009)

Ouch!  :mecry:

Variable speed also can be helpful, crawling the chuck around to check clearances or approach the end of the cut is really nice. Little momentum at crawling speed.

-- Alan


----------



## will (Jan 24, 2009)

I use a reverse cutting tool for inside threads. Put the lathe in reverse and cut on the way out. I cut a clearance groove inside, position the tool in that spot and go from there.

I generally spin the chuck by hand on the last 2 threads on outside threads. I also put a clearance groove in the back.


----------



## Mirage_Man (Jan 24, 2009)

will said:


> I generally spin the chuck by hand on the last 2 threads on outside threads. I also put a clearance groove in the back.



Hard to do on a geared head. Especially if you're cutting the threads at like 80rpm. On my lathe it takes quite a bit of muscle to get it to turn by hand at that gearing.


----------



## kromeke (Jan 25, 2009)

Mirage_Man said:


> Hard to do on a geared head. Especially if you're cutting the threads at like 80rpm. On my lathe it takes quite a bit of muscle to get it to turn by hand at that gearing.



Just put it in neutral and turn by hand. The leadscrew should be geared separately from the spindle drive. I can turn mine easily in neutral and the leadscrew turns with the spindle.


----------



## Mirage_Man (Jan 25, 2009)

kromeke said:


> Just put it in neutral and turn by hand. The leadscrew should be geared separately from the spindle drive. I can turn mine easily in neutral and the leadscrew turns with the spindle.



But wouldn't doing that loose the exact gear point you're threading at? IOW when you re-engage the gears the position of the threading be off? Maybe not much but not exactly the same spot? Did that make sense?


----------



## will (Jan 25, 2009)

Mirage_Man said:


> Hard to do on a geared head. Especially if you're cutting the threads at like 80rpm. On my lathe it takes quite a bit of muscle to get it to turn by hand at that gearing.



Mine is a belt driven mini lathe, easy to turn by hand.


----------



## kromeke (Jan 25, 2009)

Mirage_Man said:


> But wouldn't doing that loose the exact gear point you're threading at? IOW when you re-engage the gears the position of the threading be off? Maybe not much but not exactly the same spot? Did that make sense?




On a properly designed gear head, it shouldn't matter. I would think that most are "properly designed". 

On my lathe, I have a spindle gearbox, up top. Down lower, the feed/threading gearbox. On the back of the headstock, there is usually a removable cover to get at the changegears. Mine has 4 small change gears to get all inch and metric combinations. Under the cover, you can see that the leadscrew gearbox is tied to the spindle exterior to the spindle gearbox. It is a separate gear train.

You can change to any spindle speed in the middle of a theading job and not loose the synchronization. If you change the threading gearbox settings, then you might well loose your sync.


----------



## cmacclel (Jan 25, 2009)

Mirage_Man said:


> But wouldn't doing that loose the exact gear point you're threading at? IOW when you re-engage the gears the position of the threading be off? Maybe not much but not exactly the same spot? Did that make sense?


 

Post 24 


Mac


----------



## modamag (Jan 25, 2009)

Major bummer, will.
FYI: I saw a set of 6x jaws for ~$150. You might have to grind though.

I don't do much threading (or anything these days), but when I do I try to leave 0.060"-0.100" clearance. The HLV thread stop also helps out alot.


----------



## wquiles (Jan 25, 2009)

precisionworks said:


> +1
> 
> The best $10 you can spend is for a pair of mag-backs for two of your indicators:
> 
> ...



Yup, I have those already - really useful:





Will


----------



## wquiles (Jan 25, 2009)

modamag said:


> Major bummer, will.
> FYI: I saw a set of 6x jaws for ~$150. You might have to grind though.



Linkie? 

Will


----------



## SafetyBob (Jan 27, 2009)

Neighbor uses those dial indicators on his mini-lathe all the time...and now that I see them here I can't believe I didn't get the clue earlier. 

At least I know what to do at home tomorrow since everything will be closed due to the ice. Any particular place a favorite for those magnets? 

Bob E.


----------



## wquiles (Jan 27, 2009)

Got mine from CDCO Tools:
http://www.cdcotools.com

Will


----------



## SafetyBob (Jan 27, 2009)

Thanks Will, I will order a couple tonight, I cannot believe the rediculously low price on them. 

Still trying to figure out why I haven't done this before.......

Bob E.


----------



## wquiles (Jan 27, 2009)

Anglepoise said:


> Will,
> We all have our 'pet' procedures and as you get to know your new machine, you will adapt yours ...



Well, I finally have done just that. I now have a nice, safe, and repeatable process in the new machine. I am using a combination of the DRO "and" the dial on the carriage - it is working great 












and the resulting threads work perfect - in fact, I like these threads better in this heavier/stiffer machine than in my 8x machine:





Will


----------



## will (Jan 28, 2009)

Dust Off? 

I bought an air compressor years back to blow out the sprinklers for the winter. I use that, low pressure, to blow out the chuck on occasion. I also invested in a few different size tube brushes ( http://www.solobrushes.com/ ) . The tube brushes are the best for cleaning out the inside of anything that has been threaded. There is also a shop vac, that gets used first to get the major chips picked up.


The air compressor would probably buy a few hundred cans of dust off. I can justify the cost based on other uses, not just cleaning off the lathe.


----------



## wquiles (Jan 28, 2009)

will said:


> Dust Off?
> 
> I bought an air compressor years back to blow out the sprinklers for the winter. I use that, low pressure, to blow out the chuck on occasion. I also invested in a few different size tube brushes ( http://www.solobrushes.com/ ) . The tube brushes are the best for cleaning out the inside of anything that has been threaded. There is also a shop vac, that gets used first to get the major chips picked up.
> 
> ...



Thanks much Will. I actually just purchased a small compressor to replace my "addiction" to Dust Off (I buy them to keep the computer's clean) - I really need to get my act together and start using it 

Will


----------



## will (Jan 28, 2009)

wquiles said:


> I really need to get my act together and start using it
> 
> Will



I bought a rubber hose for the compressor. I like that much better than the 'plastic' hose that came with the compressor. It is much more flexible. A coiled hose might work also. And - all the tools and fittings have quick disconnects.


----------



## wquiles (Jan 28, 2009)

will said:


> I bought a rubber hose for the compressor. I like that much better than the 'plastic' hose that came with the compressor. It is much more flexible. A coiled hose might work also. And - all the tools and fittings have quick disconnects.



Mine came with the coiled hose as well:
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=93796

One tip that Barry also gave me was to use it on the coolant-through boring bars to keep debris out of the cutting tip - I have yet to try that 

Will


----------



## wquiles (Jan 28, 2009)

Will, I finally got the little compressor going today - no more Dust Off :devil:

















All I need now is some sort of box/enclosure to keep it quieter while running - it is a tad too loud 

Will


----------



## precisionworks (Jan 29, 2009)

> some sort of box/enclosure to keep it quieter while running


There are quite a few plans available ... most involve building a box around the compressor, lining the box with sound absorbent "egg crate" foam, and installing a small fan to pull cool air over the compressor. Here's one:

http://www.cianperez.com/Photo/Expo...ssor_Enclosure/Pages/Compressor_Enclosure.htm

I've thought about building an enclosure attached to the shop, putting all three compressors there (each is a 60 gallon vertical, 3 actual hp, 11 cfm). The cold weather, in particular, is a concern. Right now, all three pumps kick on at staggered pressures - the first at 100 psi, next one at 95, the last one at 90. 

My big air user is the Exair Adjustable Spot Cooler (vortex cooler). Mine is set to use 15 SCFM, and often uses less because it's controlled by a pressure regulator. It is a life saver on the mill, especially when side milling aluminum, as the twin air nozzles keep the shavings blown out of the end mill flutes.

http://www.exair.com/en-US/Primary%20Navigation/Products/Vortex%20Tubes%20and%20Spot%20Cooling/Adjustable%20Spot%20Cooler/Pages/Adjustable%20Spot%20Cooler%20Home.aspx

You can see the twin nozzles in this photo, just to the right of the end mill:






Another benefit is that it blows away hardened chips (both stainless & high carbon steel chips will harden as they are cut). Recutting hardened chips is a tool killer.


----------



## will (Jan 29, 2009)

I have a 4 HP 13 gallon compressor, it is LOUD. I generally turn it on, let the tank fill and then turn it off. For the most part, there is enough pressure to last a session. I use the vacuum more often to clean up chips. I do a mix of aluminum and wood on the lathe, blowing the wood chips creates a lot dust.


----------



## Alan B (Jan 29, 2009)

Using compressed air near the lathe can blow chips into places you NEVER want them to get.

-- Alan


----------



## will (Jan 29, 2009)

Alan B said:


> Using compressed air near the lathe can blow chips into places you NEVER want them to get.
> 
> -- Alan



Yep - that is true. I made a few plastic covers for areas that were problems with chips. The carriage hand wheel back area was open, the gears were getting all kinds of junk in there. A piece of fitted lexan fixed that. The other area is the top of the motor controls, the power switch. I put a soft plastic cover over that. The rest of the lathe is reasonably well sealed. One area that remains a problem is the chuck. Every once in awhile I get chips in the threaded area that holds the jaws. I remove the jaws and blow that out while I turn the chuck handle.


----------



## Mirage_Man (Jan 29, 2009)

Alan B said:


> Using compressed air near the lathe can blow chips into places you NEVER want them to get.
> 
> -- Alan



+1 I had to completely dis-assemble my 6-jaw due to getting chips inside it. I use compressed air very sparingly near the chuck now.


----------



## wquiles (Jan 29, 2009)

Alan B said:


> Using compressed air near the lathe can blow chips into places you NEVER want them to get.
> 
> -- Alan



Good point - thanks Alan 

Will


----------



## wquiles (Jan 30, 2009)

precisionworks said:


> There are quite a few plans available ... most involve building a box around the compressor, lining the box with sound absorbent "egg crate" foam, and installing a small fan to pull cool air over the compressor. Here's one:
> 
> http://www.cianperez.com/Photo/Expo...ssor_Enclosure/Pages/Compressor_Enclosure.htm
> 
> ...



Thanks Barry - I have to try the "box" idea soon 

Will


----------

