i still need to build a enclosure, when milling metal those chips go everywhere. its 340x320x100mm with a 1.5kw spindle and closed-loop steppermotors. using a 1/8" 90° engraving bit ... https://www.youtube.com/watch?v=byKxKo4NLfE

A 3d printed solenoid four cylinder engine. the plastic parts where printed in gone go, no assembly required except putting the modules (each cylinder is its own module) together and attaching the solenoid to the piston rod. its printed in PLA and lubricated with titanium grease. in tests it ran for 2 hours straight and i couldnt notice any wear. so no bearings necessary. its using a magnetic absolute angular encoder made from two linear hall sensors, one 90° rotated. their voltage is fed into an arduino and converted from Sine & Cosine to Radians to Degrees, where i pick my cylinder firing order and timing from. by varying the sensors position and rotation i can modify it on the fly. but later i keep it in code no more fiddling. earlier timing means more speed, later timing more torque and loud knocking. everything is still WIP, the flywheel is just stuck on there with no supports. ... https://www.youtube.com/watch?v=Gk8dgeXRbNU