Is anybody running these servos on a round column or square column mill (with ballscrews)? They are the Ametek 38VDC / 1150RPM motors. The RPM seems a little low. I am thinking 0.2 pitch ballscrews and 2:1 reduction would give decent torque and speed, but I'm not too sure
I ran the same ametek motors as you have on a bridgeport mill, 2 to 1 on ball screws. No the fastest by all means, but they did do the job.
The ameteks will be fine for your rong fu mill, those little mills can only cut so fast.
I had the servos on gecko drives at first with mach 3, after many hours of screwing with the stuff, I ditched it, and went to a centriod controller that work excellent.