I designed a 3 string guitar that is similar to a ukulele and a cigar-box guitar. This instrument is highly customizable and the parts can be swapped out. There are no rules on how to play this instrument. I play mine like a baritone ukulele, tuned to open G (GBD), but you can experiment with strings and tuning.
This project is still a work in progress. Print at your own risk.
To do: Create updated information about building your own.
For now: Parts list to build one are listed here:
https://www.printables.com/model/480716-baritone-triotune-playable-3-string-instrument
There are two kinds of necks to choose from. If you choose the old style neck, the headstock will be flat. With the new style neck, the headstock is angled, which does help with string buzz. I do recommend sanding the neck down as the 3d printed frets may be sharp.
There are also two bodies to choose from. One of the instrument bodies is a circle and another is a crescent moon.
Coming soon:
I've designed a new and improved soprano 3 string instrument, but I need to work more on that one. I've also designed a harp guitar version and a 3 string guitar that uses a piezo pickup under the bridge.
The author remixed this model.
Made lots of changes, not all shown here. Guitar that uses piezo pickups, harp guitar, new necks.