On or around Tue, 05 Feb 2008 17:57:02 +0000, Charles Ping enlightened us thusly:
I've got a dieholder which fits in a chuck, and I run that under power on M8 threads on mild steel, with a chuck in the tailstock. The student in low gear runs at about 30-summat, ISTR rpm. It needs watching and coolant/lube but it has a saftey feature that if you don't tighten the chuck too much it will only transmit so much torque, and so if it jams, it spins the holder in the chuck.
No doubt one day it'll all go bang and the die witll fall apart or something :-)
Hmmm. that reminds me, who sells LH metric dies? I need a new M8x1.25LH, as mine is more split than it's supposed to be. I may say that I didn't break it.