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View Full Version : Help - stuck chuck, stripping gears on Craftsman 6x18



TN Pat
01-12-2014, 10:57 AM
Hello all.

I have come upon a conundrum, folks. I have a Craftsman/Atlas 6x18 lathe, and I decided to try to take the chuck off. I'm looking at trying to find a new chuck, and some other things, so I thought I might try to check what size threads are on the spindle.

So after reading a little about how to remove a chuck from a threaded spindle, I went at it. I engaged the back gear and pushed on the chuck using the chuck key, in the opposite direction of normal rotation... well, that didn't work! I huffed and puffed and strained and grunted, and nothin'.

So, I stepped it up a notch. I put a crescent wrench on one of the jaws. I tapped on it lightly with a hammer, sprayed the chuck with some WD40... well, nothing.

After that, I decided to just put as much pressure as I could on the wrench. Now, here's my problem: in doing that, I've chipped off about three teeth from both the back gear and spindle gear. It still works and I rarely use the back gear anyhoo, but uh...

Thing is, if the chuck hasn't come loose and yet it's stripping gears... what the heck do I do now? It's like a catch-22.

Looking for a little advice, fellas. I know stuck chucks come up pretty often, but... this one's a little different. Thanks, all.

Mike279
01-12-2014, 11:10 AM
Looking at your chuck from the tailstock, your chuck will come off counter clockwise. It is a right hand thread like a common bolt with a nut. I find that a solid rap with a heavy hammer gives a better impact to loosen a stuck chuck. Since you have already chipped the back gear teeth, I would use them to loosen the chuck. After that I would not use them until you replace the gear. It would be bad to lock up the gear train while using the lathe. Mike

Wheels17
01-12-2014, 11:35 AM
If you already broke teeth on the back gear, what's the point in trying again?? I've had good luck using a plumbing strap wrench on the cone pulley and a big piece of hex stock in the chuck. Use a breaker bar and socket on the hex stock, and allow the strap wrench to butt up against the machine casing. Put some plywood over the ways so that when the breaks loose you don't bash the ways with the breaker bar. If you don't have access to the hex stock, you can put a bar across between the jaws, but that's less desirable. I'd also mark the chuck and squirt penetrating oil onto the end of the spindle inside the chuck. Let it sit for a while, then rotate the chuck a quarter turn and repeat.

Another method that I've seen discussed is to cut a block of wood the length of the space between a horizontal jaw on the chuck and the bed ways, and turn the cone gear.

vpt
01-12-2014, 11:41 AM
Personally I would chuck up a hex bar in the chuck and stick an impact on it without the backgear or lead screw gears engaged.

TN Pat
01-12-2014, 12:20 PM
Looking at your chuck from the tailstock, your chuck will come off counter clockwise. It is a right hand thread like a common bolt with a nut.

Oh, you guys are gonna hate me, heh... this was my problem all along. I had read somewhere the exact opposite, and figured the lathe would turn the same direction as tightening the chuck, so I went with the opposite of that... bah. I got it off easy-peasy. Just a few light taps and off it came... I put it back on basically with the same, hand-tight and then half a dozen light taps with a hammer and wrench. I assume that is sufficient?

Thanks for helping me out, all. Sorry for taking up your time with such a dumb mistake, agh.

Ironwoodsmith
01-12-2014, 12:41 PM
Don't beat yourself up too badly, we have all been there. Joe

Normanv
01-12-2014, 12:50 PM
It's an expensive lesson that you have learned. For a tight chuck I put the short arm of my biggest Allen key in the chuck and tap the long end. I did it recently on a lathe that had not had the chuck removed for around ten years, one tap with a hammer was all it took.

Black Forest
01-12-2014, 01:27 PM
Paging Sir John! Could you please come to the front and advise this poor man.

John Stevenson
01-12-2014, 01:34 PM
Clumsy bastard

john hobdeclipe
01-12-2014, 01:39 PM
... I put it back on basically with the same, hand-tight and then half a dozen light taps with a hammer and wrench. I assume that is sufficient?

When installing the chuck, don't wap it, tap it or slap it. Just bring it up hand tight.

Mike279
01-12-2014, 01:42 PM
Nice to hear you got it off. I like to get the chuck almost to the register and give it a quick snap of the wrist to bring it home. A little less than a eighth of a turn. This has been plenty to hold them on and not enough to make them hard to get off. From an old College shop class. Mike

Boucher
01-12-2014, 02:34 PM
When you re install take a lesson from the oil patch and use a good anti-seize compound not grease which is slick. If you encounter this problem again leave it out of gear grab some hex stock and a good impact. 3/4 impact works best.

Willy
01-12-2014, 02:59 PM
When you re install take a lesson from the oil patch and use a good anti-seize compound not grease which is slick. If you encounter this problem again leave it out of gear grab some hex stock and a good impact. 3/4 impact works best.


Personally I would chuck up a hex bar in the chuck and stick an impact on it without the backgear or lead screw gears engaged.

This has been my experience as well. Anti-seize on the threads and on the register, then just hand tighten until the chuck/backplate meets the spindle.

A good 3/4" air impact and piece of hex shaped stock in the chuck will do wonders for removing a stuck chuck. The sharp impacts do the work so the more rigidly you can secure the spindle the more successful this approach will be.
You have unfortunately already found out why not to use the back gears for this purpose but it warrants repeating for others that those parts of the lathe were never designed for that purpose. Do whatever it takes to secure the spindle solidly without damage.

trackfodder
01-12-2014, 04:01 PM
I also broke some teeth from the back-gears because I didn't realize it would climb out of complete engagement. I held it in place and stuck a crowbar in the jaws and whacked it with a hammer. It came loose. Fortunately a nice guy in Tulsa was given (2) 9" SB lathes he had no use for. He gave me the "A" apron, gear-change box, and back gears to upgrade my model "C" change-gear lathe. A friend milled the groove in my lead screw to run the power cross-feed. My spindle is 1-/2 X 8. He even gave me the gear that enables me to cut metric threads.

trackfodder
01-12-2014, 04:08 PM
I will repeat something worth remembering for safety-A friend's father who owned a machine shop was gutted and thrown over the lathe because he broke his own safety rule trying to remove a HUGE chuck by putting the chuck wrench into the socket and turning the lathe on, but accidently hit reverse while it was in front. It hooked him under his rib-cage. UGH !

TN Pat
01-12-2014, 06:01 PM
Many thanks to everyone for being understanding of my mistake, and all the suggestions. Learned a lot of good stuff outta this one! Quick question - should an impact wrench be unavailable, what's the next best way to remove a chuck?

Trackfodder - Seems to me that, if possible, the best idea is to cut the power before doing any modifications... that's not always possible, but I did make sure my lathe was unplugged!

Don Young
01-12-2014, 11:06 PM
It is interesting how many people in other threads have said, 'Lock the back gears and give it a good whack, I have never even heard of anyone damaging the gears that way!'. I confess to locking the back gears, but not to get a stuck chuck loose.

jhe.1973
01-13-2014, 01:18 AM
Just a couple of suggestions I have found handy.

A wood block w/notches to fit the inverted vee(s) & a radius cutout to fit the OD of the chuck. Plus a chunk of hex stock welded to a tube to use as a wrench.

http://i1096.photobucket.com/albums/g327/jhe-1973/Shop%20tricks/Chuck%20removal/15a.jpg (http://s1096.photobucket.com/user/jhe-1973/media/Shop%20tricks/Chuck%20removal/15a.jpg.html)

The wood block takes the weight while you remove or install the chuck:

http://i1096.photobucket.com/albums/g327/jhe-1973/Shop%20tricks/Chuck%20removal/17a.jpg (http://s1096.photobucket.com/user/jhe-1973/media/Shop%20tricks/Chuck%20removal/17a.jpg.html)

And the wrench is grabbed by the full length of the jaws to distribute the force more evenly.

http://i1096.photobucket.com/albums/g327/jhe-1973/Shop%20tricks/Chuck%20removal/16a.jpg (http://s1096.photobucket.com/user/jhe-1973/media/Shop%20tricks/Chuck%20removal/16a.jpg.html)

A few years ago the South Bend lathe forum over at the Practical Machinist site had a thread on chuck removal. They may have made it a sticky - not sure. Anyhow, I grabbed this photo from there 'cuz I thought this to be a great idea, should I ever run into a need. It would not stress the back gears at all.

http://i1096.photobucket.com/albums/g327/jhe-1973/Shop%20tricks/Chuck%20removal/Stuckchuck_zps27fae182.jpg (http://s1096.photobucket.com/user/jhe-1973/media/Shop%20tricks/Chuck%20removal/Stuckchuck_zps27fae182.jpg.html)

This is for locking the spindle while you use whatever means to loosen the chuck.

darryl
01-13-2014, 02:02 AM
Putting it back on- this is my take on it. Clean all the threads, then use a bit of light oil on them and wipe clean. Don't try to remove all the oil, just clean up a bit. If you want to use anti-seize, then wipe the oil away a little more aggressively before applying that. Turn the chuck onto the spindle, and when it comes up close, take up the weight of the chuck in your right hand and turn it the rest of the way on. Don't snap it tight. It should run up crisply and stop, not progressively get tighter, which could be a sign of damaged threads or contamination in the threads. Then block the spindle in whatever way suits (sometimes there's actually a few holes in the spindle to use with a spindle wrench) and use some form of chuck wrench like the guys are talking about. Give it a good tighten, but there's no need to overdo it. I put lug nuts on tighter than I put my chuck on.

If all is well, you should find that the chuck only needs about 1/4 inch or so of extra rotation as measured on the OD to go tight from the point where it first comes up snug.

Mike279
01-13-2014, 08:25 AM
Small lathe threaded chucks installed with a snap of the wrist are going to give you a nice tight chuck that will still be easy to remove. Engaging the back gear and using the chuck key to remove it is a tried and true method. Giving the wrench a rap with your hand is all that is needed to release the chuck. If for some reason like the chuck gets rusted on, then by all means do not think the back gear will withstand a beating. These small lathes have small keys and lightweight parts. They can last a lifetime if not abused. A little common sense will go a long ways. Mike

vpt
01-13-2014, 08:44 AM
When I install a chuck on my 10" atlas I screw the chuck on till it just about contacts the register, then give it a quick fast twist of the wrist to "snap it on" and thats it.

When I take them off I do use my back gears but I make sure the gears are "loaded" before tapping on the chuck key with my hand. "loading the gears" means turning the spindle/chuck to put pressure on the gears in the way you are going to be loosening the chuck. So when you tap the chuck key the gears don't slap together. This is a drag car trick to not break gears in transmissions or rear ends (and other parts) as well. It is called loading the drivetrain so when you punch the gas peddle there is no shock to the system, everything is already loaded and the ready to just roll out.

rowbare
01-13-2014, 08:45 AM
http://i1096.photobucket.com/albums/g327/jhe-1973/Shop%20tricks/Chuck%20removal/15a.jpg (http://s1096.photobucket.com/user/jhe-1973/media/Shop%20tricks/Chuck%20removal/15a.jpg.html)

Another thing that apparently works well if you have a bar like this (I have not tried it) is to use an air chisel on the end of the bar.

bob

shoeboxpaul
01-13-2014, 01:29 PM
The impact wrench is a great idea. Amazing what those units will break loose.

TN Pat
01-13-2014, 05:42 PM
Really neat ideas, guys... I took my chuck back off and reinstalled it with just basically a light wrist-snap, so things are well again... thanks again for the help.

Thomas Staubo
01-13-2014, 06:09 PM
When I got my used lathe, it came only with one chuck, which seems to have been stuck in place since 1977.
So to break it loose this method worked very well for me:

http://imagizer.imageshack.us/v2/800x600q90/204/p1010288g.jpg (https://imageshack.com/i/5op1010288gj)

( http://bbs.homeshopmachinist.net/threads/24847 )

andywander
01-14-2014, 12:10 AM
The OP broke his back gear because he was turning the chuck the wrong way.

Using an impact wrench likely would not have worked, either, in his case.

Euph0ny
01-14-2014, 06:18 AM
When I got my used lathe...

That's a nice clean-looking Myford. Can you tell us more about it, and how it ended up in Norway? Mine came to Belgium in my brother's truck :rolleyes:

ETA: Apologies - I just followed your link and found the Myford story!

vpt
01-14-2014, 08:07 AM
The OP broke his back gear because he was turning the chuck the wrong way.

Using an impact wrench likely would not have worked, either, in his case.



That is true in this case but many cases the chuck will be actually stuck and needs some encouragement to come off.

Boucher
01-14-2014, 10:07 AM
The OP broke his back gear because he was turning the chuck the wrong way.

Using an impact wrench likely would not have worked, either, in his case.
Using the impact wrench the gears are not engaged. Turning it the wrong way would tighten the chuck but would not break the gears. Again oil or grease is fundamentally wrong for this application. A good ant-seize prevents over tightening.