Step 6: Belts and Gearing
It is recommended that you hand-drill the holes for the belt gear-shafts. Our spacing worked out to be 11.75in, but yours may vary based on your belt. It is important that the belt be tight enough to reduce slack but not so tight such that there is too much friction.
To mount the x-axis motor, it is best to move the strut closest to the gear back. After affixing the small gear to the motor shaft with gorilla glue or epoxy, align the motor gear with the belt gear. The stepper should be upside down as in the picture below. Adjust the height so that the two gears are flush. Mark this on the strut. Use epoxy or gorilla glue to fix one side of the strut to the motor - preferably the side that allows the wires to face in the y-axis direction (as seen in the photo below).
Once the motor is attached, position the strut such that the two gears are aligned. Hold the strut in place, move the belt; if your gear is off center, you may need to adjust the motor position. Once you're found the "sweet spot" so the gears mesh evenly, mark where the two new screw holes for the strut will do. Drill and mount the strut. We also found that adding two small acrylic "guides" to the bottom of the y-axis allowed the belts to move the y-axis better.
The exact process can be replicated for the y-axis. Note you may need to counter-balance the y-axis motor with a weight on the other side.