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remove stuck back plate from lathe chuck
- Thread starter bbaley
- Start date
- Joined
- Feb 1, 2015
- Messages
- 10,128
Screw the chuck/backplate on the dividing head spindle
Insert a disk on the spindle face
Thread a nut on an appropriately sized bolt (as large as practical and long enough to contact the disk)
Clamp the nut in the chuck jaws
Tighten the bolt to jack the chuck off the plate
If the nut pulls out, you can put a second nut with a washer between. Place the washer behind the chuck jaws and tighten the jaws on the outside nut. Jack the chuck off the back plate
- Joined
- Nov 23, 2017
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- 1,191
Clamp the back plate in a vise stick an aluminum bar in the spindle hole and beat on the chuck with a hammer..... lol
or use a pipe clamp or bar clamp to clamp it to a table.....
or use a pipe clamp or bar clamp to clamp it to a table.....
trying to envision this....
I like this thread because it is taking on a very "6 guys standing around staring under the hood" feel.
Also, Rube Goldberg comes to mind
not sure I can get a washer/nut in a place to put contact on the spindle. the ID of the spindle is basically the same as the ID of the chuck (with exception of the threads). but I'll keep trying to visualize this...
If brute force isn't working, then you are not using enough of it.I
I am not afraid of brute force, just looking to determine in which manner and direction to apply it
- Joined
- Feb 1, 2015
- Messages
- 10,128
If you have a 1.5-8 tpi thread on the spindle, the disk would be about 1.25 in diameter. Something smaller than the root diameter of the threads but larger than the through hole in the spindle. Place the disk on the end of the spindle before you screw the back plate on.
I would try a 1/2" bolt and nut. The bolt should be long enough to reach the disc and still have the head sticking out 1/2" or so. It should have enough threads so there is about 1/2" of extra thread when the bolt is contacting the disk and the nut is clamped in the vise jaws. Running the bolt in will put force on the disk which will push on the spindle and since the backplate is thread on the spindle, tend to push the back plate away from the chuck. Further thinking on the nut/washer/nut idea,it won't work as described. However, a flange nut would work. The nuts from your step clamp set will do.
I don't like to pound on things like chucks. Nor do I like to use heat. They are supposed to be precision holding devices after all.
I would try a 1/2" bolt and nut. The bolt should be long enough to reach the disc and still have the head sticking out 1/2" or so. It should have enough threads so there is about 1/2" of extra thread when the bolt is contacting the disk and the nut is clamped in the vise jaws. Running the bolt in will put force on the disk which will push on the spindle and since the backplate is thread on the spindle, tend to push the back plate away from the chuck. Further thinking on the nut/washer/nut idea,it won't work as described. However, a flange nut would work. The nuts from your step clamp set will do.
I don't like to pound on things like chucks. Nor do I like to use heat. They are supposed to be precision holding devices after all.
- Joined
- Apr 17, 2018
- Messages
- 536
Take a 4ft long smooth rod and weld a nut on one end. Stick the nut in the chuck and clamp the other end of the rod to up in the air to something. let the chuck drop and slide down the rod. the jaws will catch the nut and stop the chuck and the face plate will keep on going...
- Joined
- May 31, 2018
- Messages
- 184
I'd re-mount it to the lathe spindle and clamp the largest length of sufficiently solid stock in it I could find then wiggle. With the mechanical advantage of the stock acting as a lever you won't need to hit it with anything and you won't risk the hammer blows shocking the spindle bearings. I've done this myself using a 1 meter length of 20mm bar to remove a chuck and it worked a treat. Just be sure to protect the ways in case it suddenly drops. I used a piece of an old shelf on top of the ways.
If that doesn't work and you wanted to use a twisting force you could try using the chuck to grab on to a solid piece (I've got a ground anchor that would work perfectly for this - look around I'm sure you can find something suitably solid) and making a real simple pin spanner to go in the holes in the back of the chuck. I'd drill and tap 2 holes in the end of a length of flat bar appropriately spaced. You could turn down the end of the threads if you're worried about damaging the holes int he back plate.
If that doesn't work and you wanted to use a twisting force you could try using the chuck to grab on to a solid piece (I've got a ground anchor that would work perfectly for this - look around I'm sure you can find something suitably solid) and making a real simple pin spanner to go in the holes in the back of the chuck. I'd drill and tap 2 holes in the end of a length of flat bar appropriately spaced. You could turn down the end of the threads if you're worried about damaging the holes int he back plate.
Last edited:
- Joined
- Apr 30, 2015
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- 12,621
I think I'd try tapping a knife blade in between, with heat
