Correct me if I'm wrong, but fast pitch lead/ball screws have always been discouraged for use with stepper motors. I believe it's because of the 1.6 deg movement of the stepper motors forces you to have a rather large movement per step.
Servo motors use encoders. Doesn't an encoder have a very large counter that gives you better than a 1.6 deg resolution? Motion Control Products - DMM Technology is what I have in mind.
If they do have a large resolution, then would it not be feasible to run, say, a 25mm screw with a 25mm pitch? My machine is going to be roughly 5ft square, and I really don't want to be limited to low rapid speeds. I understand that screws are somewhat limited in their maximum rps, due to whipping, so perhaps a coarse pitch is where the answer lies. Any thoughts?
To add to the discussion, my machine will be a CNC router designed for wood only. I have no intention of machining metal, other than light engraving work. Any serious cutting will be done in wood. I also want to be able to do some very detailed 3d cuts.