I designed a travel soprano ukulele that will fit on a Prusa Mini build plate. I removed the headstock and put holes for geared tuning pegs inside the body. You tie strings onto the neck instead of the body. Step file included for those who want to remix.

For the side of the neck, I recommend a M5*16 bolt and for the back of the neck a M3*16 bolt. I used a 6mm x 300mm rod that I slid down the neck and body. I recommend test fitting the rod before fully assembling the instrument. I also used generic geared tuning pegs from Amazon. For the bridge, nut, and geared tuning pegs, I recommend M1*6 screws. Something small.

Update: added a fretless neck. Its more challenging to play, but should allow you to slide or play microtones

Update 2/17/2023: I made the sides of the ukulele body thicker because I had an issue where the tuning pegs were flexing a bit too much. I also repositioned the holes for the strings on the back of the body to reduce stress on the tuning pegs

Update 2/17/2023 Part 2: I also repaired the neck models. I've also included a diatonic neck that I have not tested yet. I've tested the chromatic and fretless necks (neck 1 and neck 2).