So, I have a Hercus, whose spindle is an 8tpi thread, and 1.5" OD?
Tried to borrow and fit a 4jaw chuck, from a Boxford lathe.


1) Had a hell of a time getting my existing 4" chuck off. Tried gripping the drive belt, then hammering a wedge in the headstock under the pulley, then engaging the back-gears. This faceplate seems to lock on to the step in the spindle, so I will try oiling spindle before re-fitting (both threads are clean)

What do other people do to get threaded face plates off? How do you "lock" the spindle?



2) The borrowed chuck wound on about three quarters of a turn, and stopped. Its threads are clean.

On the bench:
IMG_0238.jpg
the Bernard 4 jaw (on the left) has a thread which is about 10 thou smaller in diameter than the Pratt (on the right).


Have any of you guys noticed such a variation between face plates or spindles?

I haven't measured the two spindles accurately yet (only have 1" micrometers),
but does it really mean the Boxford I borrowed this from has an undersized spindle AND faceplate?
Attached Images




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