Print in Place Harmonic Drive Gearbox

Design preview. Rendered from the file, not a photo.
This model is not currently offered as a verified ready to buy print.
What it does
- Working 94.5:1 gearbox prints fully assembled
- No supports needed, ready to spin off the bed
- Bold demo of harmonic drive and planetary gear concepts
- A standout maker shelf piece and STEM teaching aid
- Sparks great conversations about mechanical design
You pull it off the print bed, give the input a turn, and the output spins very, very slowly. That is the magic of a 94.5 to 1 reduction in your hand. This harmonic drive gearbox prints fully assembled, no supports, no glue, no bolts.
The design pairs a flexible output ring with a planetary gearset for two stages of reduction. The crinkled belt forms gear teeth on both sides, which is a clever twist on the traditional toothed-belt approach.
Use it as a desk demo, a mechanical engineering teaching aid, or a maker portfolio piece. A satisfying object that says a lot about what 3D printing can do.
8.9k downloads in the maker community. That is interest in the design on the site it came from, not our sales.
What you get
- This design prints as one piece.
- Nothing else to print or buy for this to work.
What it is made of
Designs like this print well in PLA. Compare the materials.
Printed plastic is strong for its size, but it is not metal. We have not load tested this design, so we do not publish a weight rating. Keep it out of a hot car and away from open flame.
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Who made this design
Designed by emmett. We did not draw it.
Shared under Creative Commons, credit and share alike. See the original design