According to Wes :

[ ... ]

Well the lathe that I have access to won't hand crank worth a chit unless I
leave it in neutral from the start.

If you're going to hang a hand crank on it, it *better* be in
neutral through the whole task.

And if you expect to be switching between hand cranked and
power, take the time to make the hand crank assembly well balanced, or
the lathe will be hopping all over the place. Ideally, I would suggest
a spring-loaded folding crank so it won't be out there bashing at your
hands or anything else which gets close when you have power applied.

Though applying power while you've got a hand crank mounted is
still asking for lots of trouble.

I'm curious about the lathe I'm fixing.
Since the motor and varidrive is out, I wonder if threading the whole shaft
at home using a crank is an option. I only need to turn .75" at 14 tpi.

It might well be. If the lathe is belt drive, disengage the pin
which transfers from the pulley to the bull gear, and leave the back
gears disengaged and you should have little trouble hand cranking. (And
be sure to back the cutting tool out of the thread before you hand crank
it back to the start position. (Though the real need for the hand crank
is when you are doing metric threading on an imperial leadscrew, where
you have to back up without disengaging the half nuts to avoid losing
your thread position.)

If it is a gearhead lathe, however, I'm not sure how to make it
totally neutral.

I'll look into the feasability in the morning. It isn't like tying up the
lathe until I get done is a problem.

Any tips on making an expanding arbor for spindle? Mine is 1 3/8" id.

Others have already suggested the expanding grip used for
bicycle handlebars. Maybe make three splits instead of two so it is a
bit better balanced.

Good Luck,
DoN.
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