I do NOT trust my z axis it has terrible back lash and repeatability issues. I measured it once at 0.023 backlash but even with compensation I still cant move the head up and then back down and hit the same zero. After reading some of the other threads on here I have come to believe that the ball nut might not be tight. I did a quick check and it "seams" to be but I think I could have been more through. So I was wondering if anyone has run into this problem and if so how did you fix it. I am not above buying another ball nut to fix the problem so if anyone know what kind of ball nut I should be looking for that info would also be appreciated. Heck I am not above replacing the entire assembly (stepper, ball screw and nut) if it will help.

FYI I did replace the motor with a MUCH heavier (lists @ 42# MTR-002-3BD36) 2HP motor. That is why I would consider replacing the stepper. But again I don't know a lot about the electronics inside the cabinet if someone could suggest a stepper that might be more powerful than the one that is on there that would be a direct replacement I would gladly take that under advisement.