Zeroed in my replacement chuck tonight.

Got a replacement 4" 4 jaw chuck in the mail tonight. It's for my Grizzly 7x12.

Cleaned it up, put the back plate on, and mounted it on my lathe.

I checked the TIR on the side of the back plate and on the side of the chuck as I turned them slowly. The back plate showed less than .001" TIR and the chuck showed about .0015" TIR.

Since the jaws are independent I know I can compensate for runout but I just felt like fiddling with it tonight to see how close I could get it.

Are those TIR's OK? What should they be?

Thanks,
Dan

[BillH]

On my 7x14 lathe, the best I could usually get something zeroed in was around .001 with the 4 jaw, however I tribute that to my own skill in zeroing the chuck. Its not exactly easy, takes practice. I got ways to go still.

[Forrest Addy]

It's nivce if the face run-out is as close as you have yours becauseit makes a handy reference plane for some jobs. Otherwise all a 4 jaw chuck has to do is run in reasonable balance when chucking accurately dialed-in round work.

[pgmrdan]

Good idea Forrest. I'll check the face of the chuck tonight. It would be nice to know how close to perpendicular to the axis the face of the chuck is.

I've never gone to the trouble to check the runout of this machine before so I don't know how close is good enough but it seems like it's pretty good for what I do.

[BillH]

the run out of the mt3 taper in the headstock on mine is .001 which is bad, however the spindles outside register is less than .0005.
It really doesn't matter though, I can make my lathe deflect .010 just using my index finger pressing on the correct part. Cant do that on my south bend.

[This message has been edited by BillH (edited 01-29-2004).]