I'm starting a scratch-build. It will be a dedicated purpose tiny desktop CNC lathe. It will be probably smaller than a HF mini lathe but weigh twice as much. This will not be a hobby machine. It will be putting in serious hours. I want it to be fast, accurate, rigid, robust.

I am debating about what motors to put on it. I would like to save money where possible. AC servos would be ideal but they're expensive. There are some ridiculously cheap ones on eBay, $150 for 500W motor + drive. I assume they're crap and should be avoided, but thought I would check here and see if anyone has used them and had anything to say.

Also considering the hybrid stepper w/ encoder feedback option. Never used those, are they any good? Can they hold their own against an AC servo?

Also considering DC servos. I would have no qualms using DC servos but I can't seem to find any. Where can one buy decent DC servo motors?

BLDC? I know very little about them other than they seem to have much lower torque specs than the other motor technologies for a given size. I have that notion only after a cursory glance, I could be way off.

This will be a LinuxCNC machine, and I'm considering using one of the Mesa boards to drive the servos. Does anyone have anything to say about their motor driver boards? 8i20, 7i39, 7i32, 7i54, etc. etc.?

This will 100% absolutely have closed loop control no matter what motors are chosen.