Flat plane 4-cylinder engine crankshaft. This crank matches my piston/rods: http://www.thingiverse.com/thing:100282 This design uses my custom counterweights, main journal, and a hexagonal head on the flywheel end to allow for cranking. Print both halves at once, or print separately for make benefit glorious short print times.My PLA print settings: Layer Height: 0.5009 Honeycomb 0.25 fill