Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

My Stuart dynamo has what appears to be a combination pulley mounted on its 5/32" shaft. There is a round belt pulley groove which has a max. O.D. of 3/4" that is 7/32" wide and contains a groove .100" wide, with a 9/16" diameter at the groove bottom. Outside of that is a collar section for a flat belt with a 3/8" O.D. that is 9/32" wide, with a single tiny slotted setscrew, and showing no crown.

Hope that is of some help.