I am turning cylinders with a diameter of 12 mm but each cylinder has a diameter that is always smaller than a tenth (12mm, 11.9mm, 11.8mm etc.) the offset of x moves instead ze 'perfect. why '?

Hi,
at a guess I would say that you have a conflict with your BoB and stepper drivers.

Lets say your stepper drivers are active low whereas you BoB has a pull-down resistor. In that circumstance
if your controller offered 20 steps CW followed by 20 steps CCW your steppers would advance 20 steps CW but
only 19 steps CCW.

Craig

hi thanks for the reply the settings are ok. the fault is the faulty motor driver.