How do I get the chuck off.

[David Pollard]

Hi There,
I have recently bought what I think is an early model Atlas v42.
I have lots of things to figure out about how these machines work.

One obvious question is how do I get the chuck off. I can see it unscrews but what is the procedure? I don't want to break anything.

Thanks
David

 

[mattygee]

It all depends on the condition of your lathe...is it rusted on or just real tight.. If your lathe has backgears you can engage the backgears with the pulley pin engaged and carefully use a screwdriver laid across the chuck jaws and lever it off. An alternate is with the drive line engaged but still free to turn tighten a large allen wrench, breaker bar etc in the chuck and judiciously hit it with a dead blow hammer to break it loose. I've had decent luck just using the chuck key inserted into its recess in the side of the chuck and hitting it at the base. I'm sure others ill have alternate methods, but the first rule is (try) to do no harm. Any method you use has to be measured against the likelihood of tweaking the chuck or breaking something downstream. If its rusted, a little heat applied to inner of of the the chuck goes a long way too... Good luck! I know someone will chime in a shoot down at least of these as fatal to the machine, but it is all about common sense and there really is no surefire way to get these off if they don't want to.

M

 

[David Kirtley]

One of the nicest solutions I have seen is to get a piece of hex bar and chuck it up. Then you can use a wrench on the hex bar. (Idea credit to doubleboost on Youtube)

 

[wa5cab]

David (pollardd),

If the chuck is merely at its normal "tightness" and not actually stuck, the (or a) standard way of breaking it loose is to rotate the spindle until the square socket is about at TDC. Engage back gear without pulling out the pin. Insert the chuck key in the socket, grasp with one or both hands, push away from you to take up the slack, and then pull sharply toward you. After it breaks loose, remove the key and disengage back gear. Then with your left hand placed under the chuck to catch it when it runs off the spindle threads, unscrew it with your right. For heavy chucks you may want to make a catch block out of a piece of 4x4.

If that doesn't work after three or four jerks, then you'll have to resort to one of the methods previously mentioned. I would not use the back gears to lock the spindle if you actually have a stuck chuck situation. A safer method to hold the spindle is to slack the spindle drive belt, move it to the largest spindle pulley groove, and with your left hand, squeeze the upper and lower part of the belt together and pull toward the rear. Or cut an old belt, put it around the largest pulley groove and pull forward (towards you) and against the front of the headstock while applying torque or impact to the chuck. Or use a large non-metalic strap wrench around the bull gear (large spindle back gear at right end of headstock). The latter method is I think the best of the three as it keeps the shock load off of the pin and the area of the bull gear and pulley that it runs through.

Robert D.

 

[David Pollard]

I'll start with the safest suggestions first, and let you know how it goes.
I don't believe it is stuck but it probably hasn't been off for a lot of years.
Thanks for all the suggestions.

David

 

[David Pollard]

I didn't have any Hex bar around so I found a large Allen Key and put that in the jaws.
15" Shifter / Monkey Wrench for you guys in USA on the Allen Key.
Low speed on the pullys hang on to the belts and couldn't move it.

Engage the back gear and just a little preassure on the wrench.... bing, off it came.
The thread on the spindle is in excelent shape.

Thread on the mounting plate for the chuck is looking a little average but still easily classed as serviceable.

So problem solved with a good outcome.

Thanks to all

David

 

[drs23]

I didn't have any Hex bar around so I found a large Allen Key and put that in the jaws.
15" Shifter / Monkey Wrench for you guys in USA on the Allen Key.
Low speed on the pullys hang on to the belts and couldn't move it.

Engage the back gear and just a little preassure on the wrench.... bing, off it came.
The thread on the spindle is in excelent shape.

Thread on the mounting plate for the chuck is looking a little average but still easily classed as serviceable.

So problem solved with a good outcome.

Thanks to all

David

Another 'happy ending'! Don't ya just love this place?

I do.