Following up on Ernies suggestion of using a lathe for tubing coping, I gave it
a try and it works really well. For holding the tubing, my Aloris boring bar
holder worked really well with the added benefit of being able to quickly
adjust the tubing position above or below the centerline of the mill for weird
off center copes. The Aloris tool holder I have is sized 1" with a bushing to
allow clamping 3/4" . I see in the J&L catolog that Aloris also has a holder
that would do 1.25" and 1". These 2 holders will cover most of the tube sizes
we deal with. I set the lock screws firmly but not rock hard and did not mar
the tube. It was necessary to debur the edge after coping to get the tube out
of fixture- it's a snug fit.
All in all I'm very pleased and again thanks for the tip.