YACS Yet Another CNC-cut Spirograph cnc/laser

This is YACS, yet another cnc-cut spirograph. As a specialty it uses hypocycloidal (round) teeth which allows optimized machining on a cnc, as the tooldiameter has no problems on small teeth like with the sharp edges of involute gears. Furthermore I added not only holes, but three triangles on each planet gear. This results in interesting shapes. As a gearset I decided to use 48, 50 and 52 teeth for the sun gear and 39, 40 and 42 teeth for the planet. This results in 9 different rosettes:

My build was done on a desktop cnc-machine by Stepcraft using a spiral-toothed 1.2 mm flute. I used Pertinax I got from as a donation from a reader. This material is perfect for the task: it's hard, extremely smooth and can be machined well. Be sure to cut the inner wheels first!

A laser cutter might be a good alternative tool to create smaller versions. Please be aware that the stl-file is not tested. It's for viewing only.

Visit https://www.zenziwerken.de/en/Spielsachen for more toy designs.