NEMA 17 50:1 Strain-Wave Reducer Kit
Three-piece print-in-one-go strain-wave (harmonic) reducer for a NEMA 17 stepper: an 85 mm housing with the 31 mm M3 bolt square and 22 mm pilot recess that carries a 102-tooth internal ring, a thin-wall 100-tooth flexspline cup with a 20 mm square M3 output pattern, and an elliptical wave generator that grips the 5 mm motor shaft with an M3 set screw. Module 0.75 teeth give 50:1 in a 30 mm tall stack; the pieces print side by side joined by snap-off sprues.
robotics nema17 gearbox harmonic-drive