Not sure if this is a bug or if I am just missing something:
With the steel recipe there is a Brass Gear Wheel (made from 2 copper plate and one zinc plate) and a Bronce Gear Wheel unlocked. I can't find these anywhere in the crafting menu or in any machine menu.

All other gear wheels (for example stone, iron, steel ...) are in the intermediates section in the crafting menu, but not these two. Where are they crafted?

I am not talking about the gear wheel production with molds, there all gear wheels are producable (as far as I can tell).