Hi,
I am helping a friend who bought a Mercer Traction Engine kit many years ago to convert it to a Showman's Engine. The original flywheel wobbled a bit so a new one was made, sadly the crank shaft is a little bent as well so the result is far from perfect. Along with the flywheel a pulley for the dynamo and a flat belt were made.
https://youtu.be/YGZvpyGu_s0Take care Tony.