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Removing a stuck lathe chuck

cheapskate

Plastic
Joined
Apr 10, 2008
Location
Western Kansas
I am trying to remove a very stuck 12 inch 3 jaw chuck so I can put a 4 jaw on and I can't budge it. I have done the easy stuff with cheaters and even put a big bolt in it and tried the 1 inch impact with no luck. I think the last time the thing was off was probably before 1971 so its been a while. Its a very old but very tight lathe and I am not real excited about putting heat close to the bearing but I am running out of ideas? The inspection date was 97 so I figure its probably bronze or some sort of babbit and since it is pretty accurate I don't really want to go down that road if I can avoid it.
Thanks for any ideas.
 
I would recommend before you go doing anything more, post the Brand and Model of the Chuck here, maybe a picture.

R
 
If your chuck has a removable back plate take the chuck off the plate turn the plate off the spindle, then make a new plate.
 
If the lathe was built in 1897 you are certainly correct that it has Babbitt bearings. You are not going to get it hot enough to melt babbit until the paint peels off and the grease/oil catches fire. Lead is something like 400 degrees. just warm it up to a warm cookie sheet temperature (350) to loosen the joints.
By 1930 South Bend was steel on cast iron bearings. 1971 would be ball or roller bearing.
Bill D
 
Don’t know what make lathe it is, dose it have a spindle lock?
I wouldn’t use the back gears to lock the spindle, gears can and do brake.
You may be able to wedge wood between bull gear and casting to lock spindle
What kind of lathe is it ?.
 
Try this, Chuck a large bolt in the 3 jaw. Use the largest wrench you have on the bolt head. I use a spud wrench or an 18" crescent wrench . Heat the back plate with a heat gun. The first time I tried this was with my own lathe. After about 5 minutes or so I pulled on the wrench and the chuck came loose with no effort.
Second time was for a friend that bought an older lathe , I think it was a Logan , early 40's. This chuck seemed to be on the spindle since it was delivered. I tried the heat gun, wouldn't break loose. Soaked the back plate and spindle with PB Blaster. Waited til next day, then tried again.
Finally I used a propane torch instead of the heat gun. This worked, chuck broke loose with some effort.
 
Liberally apply penetrant soaking into the threads. As said earlier chuck a long steel or heavy wood bar perhaps five or so feet in length. You can whack it with a mallet or if that doesn't work hang some weight at the outboard end and leave it overnight. Chances are good the chuck will have loosened by morning. I've done this a couple times and it works.
 
There is a thread that addresses this problem that outlines a technique that has been quite successful for many.

I was threading a chuck onto my SB and the garage phone rang, or some distraction, I forget. But lost track of what I was doing when I came back. The chuck was left almost threaded on, maybe a turn or two short. But I came back after the distraction and hit "power on". The "clunk" of that chuck as it was forced on I felt through the floor. Nothing I could do would loosen that chuck. Penetrating oil, applying heat, chucking hex bar and applying the impact driver, bar in jaws hitting with hammer... Nothing would even budge it. But using this technique it was removed and no harm to the gear train.

Follow this technique. And if it doesn't work then turn off the back-plate when nobody is around to ask you why ;) ...

http://www.practicalmachinist.com/vb/south-bend-lathes/how-remove-stuck-chuck-tutorial-165028/
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My chuck was stuck pretty good.

Last thing I wanted to do was to lock up the bull gear. Teeth get pretty expensive when broken.

Took a bar, put it between the jaws at a 90 degree angle to the bed

Put a block of wood on the ways to protect them.

Unlocked the spindle. No belts, no gear engaged.

Repeatedly spun the chuck, with bar, against the block of wood on the ways. The momentum of the spin, and the relatively soft thunk against the wood, loosened the chuck in about 4 attempts. Didn't break anything either :D
 
I cut a pair of slots on the back of the spindle to engage a piece of keystock. The keystock is held in an attachment I made that clamps to the spindle. The attachment has a two foot rod I can hold onto.

I made a hex (square for 4-jaw) plate from 1/4" bar stock and cut a 1/2" square into it. I mount this piece in the chuck and put a 1/2" breaker bar into it. Turn the bars in opposing directions to unscrew the chuck.

I'll add photos later, if I remember...
 
I'm with True Temper. Cut the backplate off and make another. Quicker than fooling around with all the other methods that may or may not work.
 
No...

Place the belted speed in the lowest it can go without back gear.

Place a chuck key in and place it directly towards you.

Get the biggest hammer you have and while applying tension down on the chuck key tap the key nearest to the chuck.

The large hammer has a lot of energy that transfers well while small hammer needs large swing that breaks things.

Also consider clamping belt together between cone pulleys to add brake power.

This is process described in old manuals so it is "official" so to speak.

Make sure you apply pressure to chuck key to insure everything is in contact so the energy is transfered to the threads.

Sent from my SAMSUNG-SGH-I337Z using Tapatalk
 
Heat, applied with the biggest rosebud you can get. You will be surprised how long it takes to warm up your chuck, even a little. Heat the chuck until the spindle mount is hot to the touch. Then, all the above routines will work. Regards, Clark
 
I agree with previous post. If the chuck is threaded on, put the key in the chuck. No back gear. Hold your hand one the belt driven pulley and hit the key with a lead hammer. Sharp blow! No pussy footing! Done hundreds of times.
 
if the chuck is threaded on, evenly heat up the chuck until the spindle is warm.

put ice cube in the spindle, apply torque immediately.
 








 
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