Hi Mohamed,

True backlash in opposite direction can vary but more than likely comes from drawtube tilting than gear train backlash, which is more repeatable -if- the gears are fixed to the shaft and do not ride on the shaft they are mounted to. Coming from drawtube tilt also implies amount may change depending on how far the drawtube is extended.

Here is a video I did of a stepper motor head used, gears only in the head. Repeatability is good considering any slip that may have occurred of the dial indicator on the moment arm and the 5 pound weight hanging from the 2 inch moment arm

Stepper motor head video from 2012

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