Geared rotary piston drive

THE DESIGN HAS BEEN UPDATED. PLEASE SEE THING 1098809.

This is a model of mechanism 329 from http://507movements.com/
Designed in MOI. Made on a Robox from Robox ABS.
As you can easily see the surface finish is poor. This in NOT a reflection on the engineering or precision of the Robox, merely the less-than-fully-developed state of the software.
So, the model doesn't look as nice as it should, but works fine, as your can see for yourself in the video: http://youtu.be/dvHLU3Owg_Y
As you can see in the video there is a certain amount for flexing going on reflecting the limits of accuracy of the FDM process - and the clearances that I provided. Making in PLA may require more extensive post print finishing.
The screw holes are sized for 3mm screws. I used button head cap screws. OAL of 8mm for retention of the smaller gear and the connecting rod, 10mm OAL elsewhere.