A couple of off-post-topic question: I’m at below-novice level in machining (learning on an old, manual Bridgeport mill at my makerspace). Can you recommend any simple but functional projects for practicing skills on a mill and learning behaviors is different materials?

Also, I’m intending to machine a replacement for my electric guitar’s bridge since the stock one is both out of spec, making it impossible to find an aftermarket replacement, and it’s made of chrome-coated pot-metal, making it kinda ugly and musically poor. Do you have any suggestions for alloys that are interesting, decently machinable, and non-leaded?