It finally got the better of me... HELP!

[Sandy H.]

I'm not at all familiar with that type of lathe, but I have always seen the faceplate/chuck mounting plate made as a machined piece or casting and not a weldment. From your indicator pictures, I think you're saying that the threaded shaft is running true, but the mounting plate is out .08mm and the mounted chuck is .1mm. If that is the case, then the mount seems suspect to me moreso than the chuck and the fact that it is welded makes me wonder if it was a repair instead of the initial build. If it was a repair, then the heat of the welding process would easily draw the material in such a way that it wouldn't be true anymore.

If I've misconstrued the issue or am causing confusion, please disregard.

Sandy.

 

[go_fish]

I'm not at all familiar with that type of lathe, but I have always seen the faceplate/chuck mounting plate made as a machined piece or casting and not a weldment. From your indicator pictures, I think you're saying that the threaded shaft is running true, but the mounting plate is out .08mm and the mounted chuck is .1mm. If that is the case, then the mount seems suspect to me moreso than the chuck and the fact that it is welded makes me wonder if it was a repair instead of the initial build. If it was a repair, then the heat of the welding process would easily draw the material in such a way that it wouldn't be true anymore.

If I've misconstrued the issue or am causing confusion, please disregard.

Sandy.

Sandy,

I understand what your saying. Should i dial the face of the backing plate?

B

 

[Paul in OKC]

I'm not at all familiar with that type of lathe, but I have always seen the faceplate/chuck mounting plate made as a machined piece or casting and not a weldment. From your indicator pictures, I think you're saying that the threaded shaft is running true, but the mounting plate is out .08mm and the mounted chuck is .1mm. If that is the case, then the mount seems suspect to me moreso than the chuck and the fact that it is welded makes me wonder if it was a repair instead of the initial build. If it was a repair, then the heat of the welding process would easily draw the material in such a way that it wouldn't be true anymore.

If I've misconstrued the issue or am causing confusion, please disregard.

Sandy.

Sandy,

I understand what your saying. Should i dial the face of the backing plate?

B

Yes, make sure the face is running true. If not you can take a skim cut across it to true it up.

 

[Dale Allen]

I'd say that the more critical reading would be the runout on the stock held in the chuck.
My HF has a runout at the headstock of .002" that I just have to deal with. Knowing this allows me to compensate. If yours is .04mm either way it is not much worse.
Check to see that there are no burrs or residue in the jaws of the chuck. Put in a good 3/8" drill bit and compare the runout of that to the spindle(on the flat part not the spiral).

 

[go_fish]

Thanks everyone for your help and replies.

Heres a small update.....

Both front and rear bushes are out of the headstock. I think at some point the lathe has been rebuilt before. the above photo shows the rear bush(2 pieces) something doesnt look right to me with the rear bush. The one in the background is the front bush. Off to the bearing shop tomorrow to get some new bushes and gibs.

Ive decided to rebuild it!