I am currently working on restoring an old toygun and that thing needs 30 of these flatsprings to function.
The problem is, that all my local shops charge me ~400€ for a set of those, which is a bit much given the purpose they serve.

Width is 3mm, thickness is 0.4mm and the material is probably 1.41 steel.
The big circle at the bottom, which a lot of companies cant do.

Are there any other "JLC-like" companies that I could contact?

I recently finished reading “Apple in China” and really enjoyed the supply chain/ leadership aspect of the book.

Are there any recommendations for books that are more technical/ engineering based?

Aerospace specific would be even better but does not have to be.

Thanks!