Tag Archives: Maltese cross

A CNC Cut Geneva Drive

animated geneva mechanismA Geneva Drive is defined by Wikipedia as “a gear mechanism that translates a continuous rotation into an intermittent rotary motion.”  Although replaced by servo drives in many cases, these were once used in movie projectors and to power rotary tables in industrial assembly lines.  This is where I first saw this type of drive, and after redoing practically the entirety of these machines, the venerable Geneva mechanism was still at the heart of it, working like a champ after 20+ years.  Like most cam-type devices, they may not afford nearly the adjustability or the “easy” electrical programming of a servo of PLC controlled device, but they will run for literally decades on end with little maintenance.

So after that introduction, I recently machined one out of MDF on my router.  I plan on making one that works a bit better, and is possibly motor-driven, but check out the video below for my prototype:

This is a crude model a this point, but I’ve included the G-code and DXFs for the mechanism at the end of the article.  Everything was cut with a 5/16 inch bit that I’ve been using as a flycutter on my router, providing a relatively high pocketing speed.  Unfortunately, Read more »