Just wanted to share my penny board build.
Its all 3D printed in PLA, except for the casing and motor pulley (since it needs to take more load). So far it has survived slightly above 120km, and is able to reach 20km/h-ish. The motor does get warm, and there is a piece of cardboard separating the face from the plastic. The mounts are crudely bound by cable ties, but I will be using countersunk screws once they arrive.
While I do have a workshop that I can use, I wanted to make one that would require minimal modifications to the board (ie no welding). Also, the 3D printing process allowed me to iterate very quickly.
The main pulley is bolted to the wheel to allow the torque to be transmitted without slipping. I originally wanted it to be a simple interference fit, but the motor was too powerful, and kept heating up and melting the plastic.
Also, anyone able to guide me on implementing regenerative braking?