Tell us about yourself!
You did not mention the wall thickness of the 2" and 1.5" square. What did you use?
Since the tube length is so critical, does the kerf matter? If so, what kerf size did you use?
I don't understand the speed description. At 5V the short gear is faster than the long gear. At 9V, the long gear is faster than the short gear. Why do the gears work differently as the voltage changes? Other than this question, this is a remarkable Instructable. Thank you.