Grinder Gears

This CAD model was designed by Oskar van Deventer, copyright (c), 21 May 2015.

Grinder Gears is a minimalistic gear transmission design. It has two outer gears, a green one with 27 teeth, and a red one with 26 teeth. Those two gears interact with the inner yellow gear. The yellow gear has 26 teeth inside the green gear and 25 teeth inside the red gear. The axis of the yellow hear is 1 mm offset to the axes of the green and red gears. When the yellow gear is turned, its center makes small 1-mm radius rotations, one rotation per tooth skip. This "tooth-skipping" type of action makes the red and green gears rotate with respect to each other because of their different teeth number. For each full rotation of the yellow gear, the red gear has moved one tooth step with respect to the green gear. This way a high reduction ratio is achieved.

The practical application of this gear transmission design is yet unknown. Benefits are its minimalistic near-coaxial design and its compactness. However, it also has a lot of friction and vibration, which may make it unsuited for a powertrain. 

Here are some links about this design.
https://www.youtube.com/watch?v=vbU1afvCRwc
https://twistypuzzles.com/forum/viewtopic.php?t=28933

Feel free to 3D-print an extra sample to give to a friend, as long as you mention the designer and don't charge money.

If you are planning to sell some samples, then please contact me for a license agreement. The royalty fee is 10% of your selling price.

Please do not upload the design to a commercial service, or redistribute the design in any way other than linking to the YouTube video: https://www.youtube.com/watch?v=vbU1afvCRwc

Enjoy!

Oskar
14 February 2025

Contact: 
https://oskarvandeventer.nl/index_contact.php?subject=Print%20It%20Yourself


