NEMA 17 Snap-Off Planetary Reducer Kit
A 4:1 planetary gearbox for a NEMA 17 stepper printed as one snap-off kit: a 78 mm ring housing with 45 internal module-1.5 teeth, a 15-tooth sun (5.3 mm bore, M3 grub screw hole), three 15-tooth planets riding on 5 mm carrier pins, a 60 mm output carrier with four M3 heat-set holes on a 30 mm circle, and a cover held by four M3 self-tap screws. The housing bolts straight to the motor's 31 mm square pattern with the heads recessed in the floor and a 22.4 mm pilot recess underneath, so an arm or drum bolted to the carrier gets four times the motor torque at a quarter of the speed.
mechanism nema17 planetary gearbox