Thread: Having trouble unscrewing chuck from lathe

Maybe unbolt the chuck from the backplate so you can spray some good spray lube into the end of the spindle/backplate. You sure don't want to break off anymore teeth. Then make some kind of holder to lock the spindle and try to turn it off. Good luck and keep us posted...Bob

Hi. I have a similar lathe. I hold a block of wood on the rear way under a jaw and bump the reverse button (don't let it latch on). You can apply more force by starting with the jaw further from the block and/or using a higher speed. It's the momentum of the chuck that does the trick rather than the motor. You have to be careful that the block is square or it can spit out.

Thanks for the idea Bryan.

Trouble is my lathe doesnt have reverse. The switch starts the lathe in forward direction in both positions.

The motor was replaced at some stage, the previous owner said when the electrician wired it up, he said it would only run one way .

Ironwood,
You could try a can of freezing spray on the inside of the spindle.


Bryan,
The momentum of the chuck would be working against you wouldnt it?

Stuart

One you could try is to take out all but one jaw, place a piece of board on the ways. Then cut a block of wood (4x2) to sit on the board and come to centre height. Place the block over towards the back level with the outside of the chuck then turn the chuck so the jaw so it is at the lowest point facing the ways and with the lathe in low gear turn on the lathe in reverse.
This sudden stop should crack the thread undone, just be prepared to catch the chuck.

Dave

Everyone posted while I was typing.

Dave

I just meant that you don't drive the chuck into the block under power. I suppose it's actually the momentum of the spindle etc that does the unscrewing. If you want to be pedantic.

Originally Posted by Stustoys

Ironwood,
You could try a can of freezing spray on the inside of the spindle.



Stuart

Hi Stuart, never heard of that stuff before, is it like a can of liquid nitrogen spray ?

If it's as stuck as he said and broke another tooth off the back gear trying, I would say it has been on for years and is going to need a bit of speed and a sudden stop to get it off.
I had a chuck like this on my old Hercus when I got it.

Dave

Originally Posted by Bryan

I just meant that you don't drive the chuck into the block under power. I suppose it's actually the momentum of the spindle etc that does the unscrewing. If you want to be pedantic.

It would be the inertia of the spindle and other masses that would try to keep turning once the chuck suddenly stopped.

I would be trying that as we speak if only my lathe had reverse as it would probably get it loose.

Is the motor reversible? Can you swap the wires over to get it to run in reverse?

Dave

Originally Posted by Dave J

If it's as stuck as he said and broke another tooth off the back gear trying, I would say it has been on for years and is going to need a bit of speed and a sudden stop to get it off.
I had a chuck like this on my old Hercus when I got it.

Dave

Hi Dave, I think it has been on there for the life of the lathe, as he didnt have a 4 jaw chuck, or anything else to go onto the spindle, which makes me think its only ever been used with this 3 jaw chuck fitted.

One more tooth off the backgear is no great loss, as its missing 3 others from a previous misshap. Which makes it useless for doing any turning with it engaged anyhow. But I dont want to damage it any more.

Originally Posted by Dave J

Is the motor reversible? Can you swap the wires over to get it to run in reverse?

Dave

Not sure on that, will have to check it out.

How about removing the motor belt and turning the countershaft backwards by hand? To allow more of a turn (extra momentum) you could remove all the jaws but one, like Dave said. A helper would um, help.