....
Joe Gwinn
I just made a set out of 6061 Al at school on Thur. Havent
used them yet but need them to hold some threads without
"buggering" them up. Havent figured out how to hold the
jaws in compression while threading all the way through
the soft jaws yet.
...lew...

In such a case, I like the jaws to project inward, beyond the surface of the
master jaw. Grip your spider (or piece of stock) on the master jaw,
allowing full access to the soft jaw. Works fine, Lew.
....

I had a project where I had to make four inch high jaws and the part
had to fit down inside the chuck (NMTB tool holder). So I drilled and
tapped 1/4 20 holes in the top of the jaws. Then a plate to bolt on. I
liked this method so well that i made a special plate to fit all sizes
with spiral slots and now I always bore my jaws this way.

Karl