Wood, Plastic or whatever. Favorite Materials.

Maybe automotive transmission gears, or Boston Gearworks if they are still in business.

The only thing left would be to turn them out on a lathe with a miller.

Reminds me of the old wringer washer my mother used to have back in the early '50's.
 
Anything can be made from anything, Balsa, card, styrene, brass & copper shim, aluminiun cans.
For N & Z Guages, copper wires in various sizes is great for pipes, trusses etc.

This bit i'll put in hints & tips it may have been covered before.

Working with any metal is much easier if it is annealed (softened)before starting.
Aluminium first cut your can into appropriate size pieces, on the plain side smear a squiggle of bar soap, then heat it over flame until the soap goes brown. Immediately quench in cold water, it's ready to use "note" working the aluminium will harden it again and make it brittle, Simply re-anneal it.

Brass, Copper are the opposite,
Brass & Copper, heat until flame colour goes greenish, then let cool naturally. And it's ready to use.