Tell us about yourself!
I made a bunch of crystal sets when I was a kid (loooooong time ago), first with cat's whisker on galena crystal, later with germanium diodes (e.g. 1N34). Most were with magnet wire coiled around cardboard toilet-paper tubes, then varnished. Some with a slider, some without. This might work better with a small capacitor (.01uF ceramic) across the earpiece.Incidentally this childhood hobby led to a very successful career as an electronics engineer, now retired. Thanks for the memory.
Nice, but a schematic diagram would be helpful.
Wow, nice job. The only thing I would do differently (if I had your skill, experience, workshop -- none of which I have) would be to set the screws in from the top rather than the bottom, so they'd be less visible.