I have seen years ago, a Bridgeport clone mill Z axis column power fed with a Nissan? used to be "Datsun 260 "cold weather starter motor.
Titon Eng CA produce a Super starter and there original motors were modified for various NASCAR cars using this motor,?
sourced from Datsun Canada. Today possibly available and cheap from car scrap yards.
This is a gear reduction motor, brushed so RPM changes are difficult, but with plenty of torque.
I believe physical size was about 5" dia x 8" long.?
The guy basically drove it off a 12V battery adjacent to the mill.?
Being it a starter motor the drive pinion only entered the gear attached to the original mill bevel gear arrangement when the button was pressed to excite the motor, so manual operation?of the knee was always available.?
Cheers
--
John
John Lindo