Devlog 4: I have printed out all of the different parts and assembled them, as you can see down the bottom there is a black piece of filament holding the connecting rod to the crank. The knob that is on the end of the crankshaft is a key way for a flywheel to allow it to spin with the axle. It needs the flywheel to take keep the momentum. when the piston gets sucked up the valve will come down and let air in. On this stroke the piston is no powered at all and if not for the flywheel, it will stop. The crank all spins smoothly and if the first big step in this project. I am now designing the main body that will house the crank and the piston.