50:1 Harmonic Drive

50:1 Strain wave gearbox (Harmonic Drive)

This is my prototype for a harmonic drive. Based on my tests this design has minimal backlash and is backdrivable. It's a bit big for what it does, so I'll be revising it for a more compact design.

You'll need a 6808 bearing, two 608 bearings, some M3 and M5 nuts and bolts. Your printer also needs to be tuned well to print this accurately.

I recommend printing the splines at a slower speed to maintain precision. The supports for the circular spline can be a bit difficult to remove. I removed mine by drilling through the holes and peeling the supports out with a pair of pliers. The flex spline can be printed in PLA and not break, but it's better to print it with PETG or nylon.

Six M3 nuts are sandwiched in between the output shaft pieces for mounting to other components. The output adapter is for mounting to my other printed projects, with all have 10mm spaced M3 holes, so it's not a mandatory part of the design. You can choose to p