This slideshow requires JavaScript.

My experiment with a multi-piece turn around didn’t work.  The idea was for a multi-segment turn around where each string could be tightened and that portion of the turn around would be able to rotate as needed independent of the other pieces.  I simply did not account for the kinds of stresses the pieces would be under through normal use and string tension.  Each segment deformed, resulting in none of them being able to rotate and the slightly less rigid turn around bowing slightly under the pressure.  I couldn’t get a great picture of the deformed parts, but perhaps this will give some idea.

This slideshow requires JavaScript.

In the end, the best result for my ukulele has been a 3D printed turn around, finely sanded smooth, unadorned by paint, with a small amount of lubricant (I’ve used machine oil) over the metal bridge and across the turn around.  These simple elements have, hands down, beat the over engineered / over designed pieces above.  If they were printed out of a more rigid material, milled or turned from solid metal, created by using a system of washers, or made using a full length bolt, I’m sure it would have worked better.

The design of my turn around uses captive nuts in the plastic core, secured by bolts on either side.  This ends up being dramatically easier and cheaper than trying to source very long Chicago bolts and posts – but has a minor downside in that the two bolts don’t actually connect.  As long as the material between the two bolt ends is strong enough to withstand the continued forces of four strings under tension, there shouldn’t be a problem.  However, even printing the turn around with the best orientation for printing strength in PLA didn’t result in a part that could withstand these forces for a long time. 1  One of my ideas for this part involved using bolts that were possible slightly longer or of different lengths so they would both tighten slightly into the same captive nut, resulting in one “continuous” piece of metal for the turn around core, then using washers to ensure / assist in minor distance adjustments.

Here’s how it looks today:

This slideshow requires JavaScript.

I don’t plan on any more improvements for this particular ukulele.  I’ve deeply enjoyed playing it since it became “finished enough” to be playable in August of 2022.  That said, I’ve been thinking about how I would create another one.

1. CNC Cut Wood.  I spent the vast majority of the time on this project just rough cutting the wood to size using a combination of hacksaw and coping saw blades.  I spent a ton more time shaving wood off the neck using rough files.  Starting with a piece of wood that was already the approximate dimensions and only needed finishing would feel like starting at the 90% mark.
2. Different Wood.  I went with mahogany for a variety of reasons – but cost was one of the biggest and dumbest of these.  The difference between a plank of mahogany for $10 and the most expensive wood from Rockler at maybe $30 is a rounding error when the project took more than 100 hours of my time.  I’ve suggest that wenge, zebrawood, ironwood, or walnut would be my choice for another attempt.  Of these, I am leaning towards walnut for a deep brown, possibly gray finish.
3. Strap Attachments.  The strap was not quite an afterthought.  I had always planned on using nylon webbing / seat belt material for the strap and had designed printed strap buttons for hooking the strap onto the ukulele, but in the end I just couldn’t bring myself to drill holes in the finished uke.  This was just as well since I had wanted to try using some paracord in a project for a while.  After using a flame to seal the ends of the paracord and webbing, the result was way too thick to use in my sewing machine and had to be hand stitched.  I’m not great at hand sewing, but it is functional.  Given the dark colors of the thread, paracord, and webbing, the haphazard stitching isn’t very noticeable.  If I really took my time with it I might be able to do a better job.  If it came to that I might want to use some silver or light gray thread to add a little pop.
4. Acoustic Improvements.  I’ve noticed a dramatic change in the quality of the ukulele sound when I place a book, empty box, or large piece of rigid cardboard between the uke and myself while I’m playing it.  I’ve thought about how this could be incorporated into a new design by creating a system for bolting, attaching, or otherwise connecting a larger section to the ukulele.  Another incredibly interesting option is the plastic sheet used by TitchTheClown.  He used thumbtacks to secure a sheet of plastic from a soda bottle against the ukulele, then a heat gun to tighten it into something like a drum surface.
5. Other prior improvements per a prior post.

1. I’d say it took about six months for the deformations to become noticeable [↩]