The idea is to build a simple differential wrist using almost 3D printed parts, and that could be used as base for other mechanisms. A robot arm, maybe. ;)

https://youtu.be/oQxnfeeXJ4E?si=8GoGizxtNNFTl4zS

Run it for sufficient long time, plastic gears needs some breaking in. Have fun, most of all! This is version zero, take it with a pinch of salt! Comments and suggestions are always welcomed! Note that plates and gears should be parallel, take your time to check all nuts, spaces between them. Run it for sufficient long time, plastic gears needs some breaking in. Have fun, most of all!

More detail instructions how to build it please check: https://nexp.pt/diffwrist.html

For academic purposes quote this project using the Zenodo's reference DOI: Charters, Tiago (2026). 3DPDiffWrist: 3D printed differential wrist. Zenodo. https://doi.org/10.5281/zenodo.23287814

Happy printing!