First Prototypes for a Cycloidal Gearbox

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Inspired by various designs online (most notably Bengloon at, I wanted to make a Cycloidal Gearbox too. I am currently thinking about building a small robot arm, given I soon have holidays.

My first experiments weren’t all that successful, because I didn’t understand how this mechanism works yet. However, I found an interesting model on Thingiverse by user otvinta3d. Even though it needed a lot of post-processing and is probably meant as a toy, it helped me understand the idea behind a Cycloidal Drive.

According to Wikipedia, Cycloidal Drives are capable of having big ratios and low backlash. This sounds suitable for robot arms! There might be some vibration issues, but I found a design by Petar Crnjak in his Faze4 robot arm that uses a counter-disk to combat this problem.

My third attempt looks very promising. So far, I have only made the cycloidal disk and the eccentric shaft in Fusion 360, so keep that in mind. Once again I would like to thank Bengloon for his idea to use dowel pins for the outer shell and his fantastic articles on his website. Here you can see an animation for my drive. I will soon order the bearings and dowel pins so I can make a first prototype. If you have any comments or would like to give suggestions, feel free to email me!