cnc tube notcher

Instead of friction drive, when above a specific size, how about a big
V block with an automatically actuated clamp. You couldn't turn at
real high rpms without ballance issues, but I don't know what sort of
speeds you cut at. It would mean that your cutter would need to cope
with something rotating around other than its center, so it could be
impossible to get workng.

At obscene prices, new, but not unheard of as surplus from the oil
patch, are 3 and 6 jaw chucks with very large thru holes. (typicaly
something like a 15" chuck, with a 6" thru hole)

If it were me, I would just make a set of bushings for each tube size
I ran. all with a constant OD, and split into two halves. (I have a
bunch of square ones, that I use on bike tubing -- I clamp one on, and
use the flats to ensure the holes are either coplanar or at a true 90
degrees. It doesn't come off untill the brazing is done. (ex: of two
90 degree miters is the down tube on a bicycle -- its a vertical,
angled miter at the head tube, and a horizontal (often with clearance
issues on top) at the bottom bracket (the tube that holds the pedal
axle))


-dp-