Advances in 3D printers have made them the tool of choice for many makers, and considering what you can do with one for well under $1,000 it’s easy to see why. On the other hand, it’s still difficult to get the kind of strength, mechanical longevity, and sheer beauty of a well-built device machined out of metal (unless you’re willing to spend muuuch more). In this case, the unit in question is a solenoid boxer 4 engine, which uses electromagnets instead of air/gasoline explosions to turn a crankshaft.
The video below focuses primarily on the creation process, turning raw materials into the magnetic pistons, crankshaft, housing, and wooden base that form the beautiful device. How exactly the timing works isn’t obvious until near the end (around 17:40), where four microswitches are installed in the base that are pushed down by the motor’s camshafts. While one could see such a thing activated via an Arduino and a motor driver, one has to admire the simplicity of such a four-cylinder solenoid that just takes off when connected to DC voltage… as I suppose is the case with a normal DC motor.
The project is a brilliant display of machine shop prowess, and seeing the completed device at the end is a fitting reward for Maker B’s hard work. Impressively, the clocks in at around 1,100 RPM when measured at the end at 7.2VDC, and from the looks of it, it should be in operation for quite some time!