DIYbanter - View Single Post - Dumb Question -- Atlas lathe bearing headplay

wrote:
I recentely disassembled the headstock on my 12" Atlas lathe to install
a new drive belt.

I'm now getting some extremely rough cuts with both SS and brass stock,
and quite a bit of vibration during the cuts.

If I put side pressure on the 3-jaw chuck that I'm using, I can feel a
slight side-play that I'd estimate to be a least a couple of mils, so
I'm suspect that the problem is excessive play in the Timkin headstock
bearings.

My problem is that I've tightened the ajustment nut on the headstock
shaft as tight as I can get it, which doesn't seem to be tight enough
since still the shaft sideplay still exists.

Am I doing something wrong, or do I need a new set of Timkin bearings?
Is something possibly locking the headstock shaft so that the proper
Timkin bearing tension cannot be achieved?
I've got a guess. I think there is a spacer that is supposed to go on
after the rear inner race, before the gear, before the threaded collar.
If you left out the spacer, the threaded collar will bottom out on the
threads before it presses the inner race against the outer. Or, you
may have put the collar on after the gear, and the spacer is jammed
against the key that is supposed to be roughly in the middle of the
gear.

Jon