Harmonic drive

http://www.harmonicdrive.net/ See Cnc buildlog

https://www.nabtescomotioncontrol.com/products/ Cycloidal Gearbox, Nabtesco

diy
https://howtomechatronics.com/how-it-works/what-is-strain-wave-gear-harmonic-drive-a-perfect-gear-set-for-robotics-applications/ from https://www.youtube.com/watch?v=xlnNj9F37MA and Tracked_vehicle

links
SRI abacus drive

https://www.youtube.com/watch?v=-065J34xC5o diy cycloidal drive by https://www.youtube.com/@LeviJanssen https://www.youtube.com/watch?v=IKkw4d7jyu0 rv reducer by https://www.youtube.com/@michaelrechtin https://www.youtube.com/watch?v=H4YZxb2E5PA from https://www.youtube.com/@BreakingTaps Today we're looking at how the regenerative cooling channels on Space Shuttle's main combustion chamber were manufactured. They used a combination of conventional machining with electroplating, in a really clever technique to mimic what we can do with 3D printing nowadays. tom stanton