Between rain storms I was able to cast up a few parts for this project and make progress...
You can pick out the patterns in the attached photos. The back sprocket portion pattern is mostly
wood with a plastic flange ring. The front ( outer) portion of the sprocket body is plastic with attached wood pieces. The one final drive pattern is cast resin ( with lead numbers) and a polystyrene flange extension to aid
the pour. I've been making good use of my sand muller and it really makes a difference in the quality of the castings when you use properly prepared sand...

Jerry