In article .com,
wrote:
hello everyone
the half nuts on my 9"hercus lathe are worn out.
I about to try and repair them. They look like a 3/4 acme thread.
Would that be right?
A hercus is a direct copy of a 9" southbend lathe, did they use an amce
or square
thread on their leadscrew?

While I don't have a South Bend to check, it is almost certainly
an Acme thread, as half nuts will not close easily with square threads,
and square threads are harder to cut.

You might be able to find a supplier with NOS half nuts from a
South Bend, an Hercus, or a Boxford (the UK maker which at one time made
a clone of the South Bend (under license, I believe, during WWI.

Any information would be greatly appriciated

You have what I know, and what I can guess.

Good Luck,
DoN.

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