We are in the process of building a small CNC 3 axis milling machine that relies on MACH 3 to control it. Both the X and Z axis work perfectly but the Y axis does not. The scale is not correct but what is worse is that it depends upon which direction it is moving. For example If I tell Mach3 to move the Y axis 40 mm it moves 45 mm and if I tell it to move - 40 mm it moves 35 mm.

I can confirm that there is no problem with the stepper motor as I have replaced the old one with a NEMA 17 from a Rotalink one with the same problem. I have tried both a Stepstick driver and an Easydriver with precisely the same results. Perhaps I have accidentally adjusted some settings on the MACH3 program without realizing.

I would be grateful for any help regarding this problem.