I am looking at possibly replacing my nema 42 stepper motors on my knee mill with servo motors. I am very familar with stepper motor operation but I am still learning about the servos.

How are servo motors sized? I am familar with the in/oz ratings on steppers but who do I know if a particular servo is sized appropriately for my mill? One of the potential motors I am looking at is a 48VDC at 6.7A.

Thanks,
Brian