[icecats]

I would like to start with 1/2 inch hex shafting and turn it down to 1/2 inch round shafting. I realize that the ideal tool for the job would be a metal lathe, but I do not have access to one.
I do have access to a Tormach 770 with the 6-inch 4th axis add-on. Would it be possible to turn down the hex shafting using this setup? Perhaps by slowly turning the stock while lowering a spinning end mill? I realize that this would not be ideal, but would it work?
Thanks

[GITERDUN]

You can buy R-8 hex collets- grip your hex material in the spindle and set up your cutting tool in a vise.

[Jim Dawson]

It would work, but not the best.

[photomankc]

It depends on the surface you need as well. The endmill + 4th axis will leave a much rougher surface than a lathe would. As mentioned the best way would be a collet in the spindle and a tool in the vice. That would give the best surface and roundness I would think.

[MichaelHenry]

Steve Simpson's InTurn is a servo-driven 4th axis that will turn around 3,000 rpm for turning or much slower for 4th axis work. It's sort of a RapidTurn on steroids. Also much more expensive.