These are picture of the procedure I used to cut the
glass tubing I was having so much trouble with.
Made an arbor for the diamond disk to fit a small
motor.  Clamped the small motor on the compound
which was set in line with the cross slide.  Tubing wrapped
with one layer of masking tape and indicated true in the
lathe chuck.  Water drip was from a gallon jug and small
siphon tube controlled by pinching with fingers and holding
over the cutting area.  Lathe running, disk motor running,
water running, SUCCESS.  Just touched up the ends of
the tubing a little bit with a diamond hone and it's done.
Thanks to all for all the suggestions and to Paul for the
disk.  It worked great and has been tucked away for
future use.
Ken.