I 3D-printed a working trombone!
It's mostly based on the design from https://www.youtube.com/watch?v=OI0A-zdRvIk but the 3D printer I used is too small to print some of those parts, so I had to get a bit creative with cutting and gluing/taping.
In theory it should sound decent, but I'm pretty bad at playing the trombone. See the end of that video for a demo by someone who actually knows how to play the instrument.
Technical details:
It's an alto trombone in F (2/3 the size of conventional tenor trombone).
The slide is quite squeaky so I lubricated it with PTFE grease which helped somewhat.
There's no slide lock or water key or F attachment (C attachment?)
I tried several 3D-printed trombone mouthpieces and the 11C from https://www.printables.com/model/484499-trombone-mouthpieces-based-on-bach-sizes-7c-11c-5g worked best for me. Most trombone mouthpieces are intended for tenor trombones which makes it harder to hit high notes on an alto using them.
The notes don't slot in that well, but on the flip side it's really easy to play false tones (a third below the 2nd harmonic) and pedal tones (fundamental frequency and lower notes) on this thing.
As I said, I'm awful at playing the trombone so I can only play up to the third harmonic, although I can hit much higher notes using a trumpet mouthpiece (but then it sounds like demented squeaky shrieking instead of a trombone)
