Quote Originally Posted by Kernow Jim View Post
I managed to sneak off to the workshop/mancave this afternoon.
I am working in mm's in Mach, the MS drivers now set to 1600, the ballscrews are 5mm pitch. After calibrating, 'steps per' worked out to 637.8 on x, 631.1 on y and 642.6 on z.
Something is wrong here if your direct driving the ballscrews so this makes me think you have a 2:1 ratio so your affective pitch is 2.5mm.

If your direct driving the ballscrews then the steps per should be 320 exactly.

How are you coming up with the 637.8 figure .? Are you using the Axis calibration in Mach.?