Bought a second-hand banjo a little while ago, but it seemed a little plain, so I thought I'd make a new truss cover for it (it doesn't need one, but it just seemed strange not to have one).
Bought a bunch of celluloid guitar picks from the local guitar shop (i think it was 20 for 5 bucks). On eBay, you can get a hundred assorted for that, but I didn't want to wait the two months:)
It turns out that celluloid machines fine with my .6 mm endmills. And the ABS that I used for the base also machines fine (never a problem with ABS).
A bit of hand filing, a little super-glue, some 1000 grit sanding, and it's done. Two things I learned doing this probject:
1. Sanding celluloid smells like camphor! 'Cause it's make with camphor!:)
2. Scotch 'yellow package' permanent double-sided tape is excellent stuff. Removes cleanly without residue and holds really well. Awesome stuff. And it's at Walmart (and even some dollar stores).
First couple of tries were just too dark, so I lightened things up as much as possible. The final one really 'pops'.