Not fully tightening small gear screws causes motor issues

Over-tightening the screws used to mount the motors can lead to the gears being pinched at an angle, preventing smooth motion

Added based on discussion below

The issue is not the motor screws but that the screws for the small gear were not fully inserted. This causes the gear to rub on the z-axis. We need to:

• Add an info box to the instructions to draw attention that screws should be flush

* [ ] Recess panel (with 'z' label) by 1-2 mm