On 2009-02-14, Lew Hartswick wrote:

[ ... ]

I want to hold a long piece of all-thread and work the end / cut off
thread out and repeat so there is no place to put a support to clamp
on. I'm thinking three small pieces sort of between the corners of
the jaws.

I just use the appropriate size of 5C collet for that kind of
work.

But if you don't have the collets, take a cylinder of brass or
mild steel (hot rolled, not cold to avoid the stresses in the material),
drill and bore to be a sliding fit on the allthread, then use the mill
and a slitting saw to cut a radial slit from the OD to the ID. Put this
in the chuck (with the slit facing away from the #1 jaw, if you want
repeatability) and when you clamp the jaws on the cylinder, it will
close on the allthread and grip it strongly.

If you really insist on threads, thread the cylinder before
slitting instead of boring to fit.

Good Luck,
DoN.

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