At 15-year-old developer tom-ilan has shared a fully parametric cycloidal gearbox project on GitHub, complete with a Python generator script for Fusion 360. The repository documents three design iterations: Version 1 was a hand‑cranked prototype validating the geometry at a 1:9 ratio; Version 2 attempted a micro form factor matching a NEMA 17 footprint but failed due to 3D‑printing tolerance limits; Version 3 succeeded as a functional NEMA 17‑driven unit with a 90 mm outer diameter.

The Python script implements the standard cycloidal parametric equations, exposing key parameters such as pin count (N), pitch radius (R), eccentricity (E), and pin radius (r), plus a precision offset for 3D‑print clearance. Users clone the repo, add the script via Fusion 360’s Shift+S menu, and run it to generate the CAD model.

Version 3 specifications include a 1:9 reduction (N=10 pins, 9 lobes), PLA construction, four M3×8 screws, two 6704 bearings, and a +0.15 mm tolerance offset. Measured output torque reaches 1.28 N·m from a base NEMA 17 torque of 0.21 N·m, yielding 66% efficiency. Future upgrades suggest replacing housing pins with MR128 bearings and output pins with hardened M2 screws to boost rigidity and efficiency.