Hi Oliver, I havenāt engraved on a bronze sheet (0,8 mm thick), but I successfully milled it using a 2 flute end mill 0,8 mm diam. The hardness is similar to brass but a little softer. I would say a mix between brass and copper. The bronze I use is regular bronze sheet (not yellow bronze) used by many jewelers. I never tried with yellow bronze before because I could not easily find yellow bronze sheets. However I think Fire gems has some. I donāt know if your design is very fine and detailed. You might want to try a fine milling bit, like 0.25 mm. However Iām pretty sure youāll be able to engrave it making a few tests to find the right setups. Good luck!
This probably doesnāt have any bearing, but I am machining some model railroad rail components from 1mm nickel silver sheet using a 2 flute .50mm diameter square-end mill. 2ipm speed and .005" depth of cut, slotting (i.e. full width cut).
Here are a couple of shots of the workpiece I mentioned in the last post. It is a series of six #10 frogs (crossing noses to the Brits) for N scale (1:160) model railroad switches (ref. https://en.wikipedia.org/wiki/Railroad_switch ). The frogs are still tabbed into the parent sheet of .040" nickel silver. I donāt actually know which alloy it is. I bought it several years ago from a knife-making supplies place. Probably 60/20/20 copper/nickel/zinc because that is the most common formulation.