[fox46]

I would try and rework the drill gearboxes. Do you have the output shafts supported in external bearings? Drill transmissions will not tolerate any kind of side load and will absolutely eat themselves from the inside out if you have the output shaft unsupported. You can only expect a drill gearbox to provide rotational torque. Side to side loading such as driving a belt or chain or roller with it without additional bearings is out of the question.

If however you are experiencing issues due to excessive torque then you could try using the slip clutch most drills have to limit the torque going through the gearbox.

I wish I had a box of BaneBot motors to give away but we are still waiting for some spares to come in for ourselves.