My new 3 string instrument

My 3 string instrument with a round body

I haven’t updated my blog in a very long time, so I will change that today with a new post about my new 3 string instrument.

This is a cross between an Appalachian dulcimer (strum stick), Guitar, Ukulele, Balalaika, and a few other musical instruments. It is roughly the size of a soprano ukulele. This musical instrument will be modular, so you’ll eventually be able to swap out the neck with a fretless neck, or swap out the nut and this will become a violin-style instrument. This is open source so you can modify it however you want.

History of this project

I made a fretless strum stick a couple of years ago, but it had several flaws. The neck would break often and the neck was very thick. I tried using Banjo strings and nylon strings and I couldn’t get a nice tone on the instrument at all. I used small nails on the bottom to hold the strings in place and even experimented with geared tuners and 3d printed friction pegs. Things would break quickly. Eventually I gave up on that project and practiced more with cad and designed other random projects. Years later, I designed a crescent moon ukulele and used that project as a template for my new 3 string instrument. Here is an image of a very early prototype of my 3 string instrument from years ago.

My trash prototype from years ago

This is a ukulele I designed and helped push me to finish my 3 string instrument project.

My ukulele that I used as a template for my current 3 string project

This is what one of my new instruments look like with the Model B body. It looks just like a mini balalaika and can be tuned as one, but there are many bodies to choose from.

New instrument with Model B (balalaika) body.

How do you make one?

I’ve designed these to fit on a Prusa Mini+ 3D Printer, but you will need to angle the parts with supports. Larger printers might be able to print with minimal supports.

You need glue, strings, geared tuning pegs, and access to a 3d printer.

First you will need to download the model:

Parts list: These are not affiliate links.

Ukulele strings:

Geared tuners:

You will also need a super glue. I like using Krazy Glue. You will also need a small Phillips screwdriver.

There are several bodies to choose from and I’ve included a .step file so you could make your own modifications.

Currently, there are 11 bodies to choose from

Once you print the neck and a body, you will need to make sure the parts will fit. Do a test fit then add glue between both the neck and body and fit the parts together. Some glues may dry very quickly, so a test fit before gluing is important. After that, you will want to lay the instrument flat where the neck will not bend forward. When I glue my instruments, I lay the instruments on a table with the frets facing down, but I leave the bridge hanging off the table so the instrument stays flat. If you have clamps, you could use those, but make sure to clean any excess glue. I opted out of using clamps.

Once you are done, you will want to add the geared tuners. Add one at a time and for screw holes, you should use a Phillips screwdriver to make pilot holes. You should have a tuner on the left side of the head-stock for the right string, a tuner on the right side for the left string and one on the back for the middle string. If you want to play left handed, you can swap the left and right tuners. If you play right handed, the left tuner should be the left bottom hole and left handed should have the left tuner on the left top hole.

Example: How the tuners should be positioned if you are playing left handed.

Here is a full diagram of the instrument

How do you tune this?

There are no rules on how to tune this or which kind of strings to use. I’ve only tested nylon and ukulele (fluorocarbon) strings. Metal strings might work, but I haven’t tested those on my current design. I’m enjoying open C tuning, where you tune the first string as C, the 2nd as E, and final string as G. You could tune this like a Balalaika, where the first 2 strings are tuned to E, and the last string is tuned to E. You could also tune this as D A D, like on a mountain dulcimer. Tune it however you want. I’ve included a chord chart for Open C tuning.

Future plans for the project

My plans are to change the neck design so you can use bolts to hold the neck in place and adjust the angle of the neck. This will also allow you to swap out instrument bodies if you want a different body shape or color. I will also change the neck to allow for different kinds of nuts, so this instrument will work like a violin or ukulele depending on which nut you use. The project will remain open source. I might take breaks from this project to focus on my large list of other projects, but I hope you give this project a try.

The end

I want to say thank you for taking an interest in my project, especially if you made it past the walls of text on this blog. End of post. I hope you have a great morning, day, evening, or night, no matter what timezone you are from.

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