[QUOTE=H.O;791140]A 0.5Nm (70oz-in) continous torque motor would give you 70*16/(4/PI/2))/16=110lbs of force minus losses. Not too shabby depending on the overall effeciency of the drive train. (What's the torque rating of the your motors?)
As a separate project from CNC on my mill using DC Servo's I also have the need for a small CNC router for cutting plastic and MDF wood. So I'm building up the JGRO router. Work is slow at the moment so every $ I don't spend on something is a dollar earned so to speak which is why I'm building rather than buying.
The Steppers allocated for this project are 280 oz-in motors that on a good day may do 750 RPM. Initial plans are for 10 TPI ACME all thread lead screws but odds are I'll end up changing over to belts. The discussion about this project is what then shifted over to DC Servo's instead of steppers. That's when I started doing the math for encoder lines per rev and maximum input for Uli's UHU ATMEL processor.