Two Cylinder Wobbler Engine

A small, two cylinder wobbler engine. It runs well on compressed air, and might even run on steam with the right filament.

Non-printed parts:

2x 608 bearings
1x 30mm section of 8mm rod (McMaster:8920k26)
1x Barbed tube fitting, 10-32UNF thread (McMaster: 546K53)
1x 1/4-20 threaded rod, 4" (McMaster: 98752A515)
2x Compression springs, large enough to fit over rod, about 0.5" long (McMaster: 943k72)
2x unthreaded spacers for M3 screw, 5mm (McMaster 94669A099)
2x M3x20mm pan head screws
3x M3 set screws


When assembling, set the two crank wheels 180° apart from each other. The pistons are sufficiently undersized that they and the cylinders should not require extensive cleanup.

I've included the Fusion 360 source file for easy modification. increased stroke length can be accomplished by increasing the crank diameter and lengthening the cylinder as needed.