Hello, I have an sx2 I CNC'd years ago. Mistakes were made! Currently XY move OKish and Z is fine for 2.5 and some 3D milling in wood and aluminum. Most cutting is around 5 IPM rapids max out at about 15-20 IPM. I can cut steel if I take it really slow. Unfortunately I need to drill with it and it just can't drill at any reasonable IPM in aluminum. I'm at less than 0.5 IPM and even then it will miss steps.

X and Y are on the original ACME .05 inch per turn lead screws and 1:1 pulleys. They are OK. a bit slow but usable. Z is on a ball screw. .5 inch per turn and a 2:1 pulley system I copied from Hossmachine. I should have taken his advice on steppers to use!

At the time I used Kelling KL4030 drivers, 40V 3A max, with a 36V psu. I also used KL23H276-30-8B. The motor was a bad choice on my part. Nema 23.

Best performance I can get with the combo is Bipolar Series at 2.1A and 8.8mH Supposedly 282 OZ-IN. I started with them Bipolar Parallel, 4.2A 2.2mH but driven at 3A because that's what the driver could do. That setup could not hardly move the table with out missing steps!

I don't wan't to spend a bunch of money on this thing. It does OKish but I plan on changing machines at some point when budget allows. However I can justify a few bucks to get drilling to work. Maybe just upgrade the Z stepper. I can get Kellling 270OZ-IN steppers 2.8A and 3.6 mH that fit the controller better or I can get a bigger controller and give my current Z stepper 4.2A at the lower 2.2 mH configuration. These options are about the same price assuming I stay at 36V.

I have also seen where people use lower holding torque steppers and get better performance because the inductance is so much lower. They claim the higher holding torque motors perform worse!