Stepper Recommendations for Prototype Rifling Machine.

Yes I am using a parallel port.

As for load in the stepper. Very minimal. Just the ball screw, which is 900mm long SFU1605 Ball Screw.

I think you might do better with a higher voltage.

You might have more luck with the hybrid (closed loop) steppers.

But as you have noted, this is probably a job for a sizeable servo. eBay is full of them.

I have the HobbyCNC stuff, Nema 34 I think, 200 in/oz, 40v ish power.

Just playing around under optimal conditions I've gotten over 400 in/min on a 5mm pitch ballscrew. But I don't actually machine anything at over about 90 in/min and don't rapid at more than 120 in/min.

Also I remember that the stepper motors act much different with load and no load. ie, hooked up to the ball screw vs free spinning.

Stepper motors, dramatically lose torque at higher speeds. At slower speeds with the ballscrews I have they make in the neighborhood of 100 lbs of force on the table. Near their top speed limit, you can just press on the table to stall it.