MyUKE

This “instructable” is about a compact-travel-silent ukulele.

In terms of DIY, my backgrounds are aero modelling and recumbent bikes.

In terms of musical instruments, I’m a bad guitar player.

Surfing the web, I met some very interesting sites focused on DIY ukuleles.
So, considering that I like to re-design “objects”, trying to find other ways to have the same functions (or improved) through solutions that are far from stereotypes, I started to benchmark and to imagine my personal interpretation of a compact-travel-silent ukulele

Here after the "make-of" this small soprano ukulele.

As stated above, I was looking for a small and sturdy instrument; something ready for travelling.

The solution has to permit to hear the instrument in an acoustic mode (even if not so loudly) or with the use of an amplifier.
On top of this, the building solutions must be easy enough to avoid any “exotic” approach, even if this experience could be useful to improve some DYI skills.
I call it “kitchen technology”.

The very first approach has been to start from existing solutions (benchmark).
A great source of inspiration has been “Circuits and Strings”, in particular the Travel Ukulele and the “Backpacker Travel Ukulele”.
Also NOBO13 inspired me with his orange 3D printed uke.

I’m used, before to make something, to explore it through 3D CAD studies.

Basically, the idea was to use plywood plates (top, bottom) plus rectangular wood stripes on both sides to assemble the body in order to avoid to start from an unique piece of wood and then proceed with a lot of carving. Standard tuners. The “Backpacker Travel Ukulele” is obviously the reference.

The second attempt was based mainly on two ideas: “sliding tuners” (like the ones used in many headless guitars) and a “cylindrical shaped body” (the body is obtained from a tube).

Sliding tuners are a project by themselves (I’ll explain all the details later on).

Once again, the web is an incredible source of ideas! The matter is to collect several ideas and to combine them in order to arrive to a solution that is the synthesis that you prefer … of course giving some added value.

Robert Murray-Smith’s videos on YouTube are bright examples of “kitchen technology”:

• video1: "Home made Ukulele or headless guitar tuning head"

• video2: "Homemade Ukulele or headless guitar tuning head"

Here after some views of the “tube-uke”.

The color of the “tube” (the bottom part of the ukulele’s body) is orange not for choice, but because the basic idea was to get it from a plastic pipe for hydraulic use of 80 mm diameter, cut appropriately.

The shape of this “tube-uke” is far more sexy than the first one, but I was a little bit afraid by the reduced thickness of the neck at the first frets and by the width of the body along the fret-board.

That’s why I started to think about a portion of a cone.

After some trial, I was quite convinced by this concept.

The first idea was to build the whole instrument with wood. The bottom part of the body was something like the following, with a plywood curved surface … like an airplane fuselage.

But then I took in consideration some changes about the way to made the bottom part of the body: carbon fiber!

Why carbon fiber? Because I had some tissue left from a previous bicycle project, because is really “sturdy”, because is sexy, because I like it, because … is it enough?

The “make-of” I’m going to describe is basically based on this last concept.

After some preliminary tests, it has been only necessary to modify the way the strings turn around to reach the tuners: the first idea (a simple aluminum tube with a slot to be inserted in the top plate) was not working properly due a high friction between the strings and the tube itself. That’s why I adopted bearings with a V grooved outer ring.

General dimensions of the instrument depend a lot from the fretboard (and the scale length) and the bridge. Remember that the distance between zero-fret and 12th fret must be the same between the 12th fret and the bridge. So the choice of the fretboard will influence a lot the dimensions of your ukulele.

Here after a 3 view drawing with the main dimensions.

The last step before making the "real" ukulele was to verify the ergonomics of the instrument. For that purpose, I cut a fake body from extruded foam (the one to insulate houses).

The general feeling was good. The fret-board and the bridge fits properly (both are from e-commerce).

And now let’s move from the virtual instrument to the real one!

Tuners are key component of the project.

The “tuners block” has been designed in order to permit easy maintenance, if needed.

Once again, let’s start with a 3D CAD concept. The pictures here after should be self-explaining

Four identical tuners are glued (cyanoacrylic glue) to a plywood base.

This base can be assembled / disassembled thanks to the slots that are engaging four screws fixed to two vertical stripes of wood that are glued to the internal face of the top-plate (in the real instrument, the screws have been changed with 4 “hooks” – see picture of the real “tuners-block”).

The 2 wood stripes are then glued to the internal face of the top-plate.

Slots and “hooks” (“L” shaped screws) enable to assemble / disassemble the “tuners-block” for maintenance.

In the first picture all the “hooks” are engaged.

In the following picture it is possible to understand the difference between the “engaged” and “ungagged” position; sliding the “tuners-block” permits to take it off the instrument.

The stroke of the sliding tuners is 80 mm.

With metal strings this is probably ok, but with nylon strings the stroke has been close to the maximum elongation needed; after the first tension of the thinnest strings, it has been necessary to unlock the strings (head side), pull them and lock them again. Not a big issue.

The single tuner is quite simple.

The major change in the real tuner is the “slide” where the string is fixed: from a dedicated piece to “something” (wing nuts) copied by the Robert Murray-Smith’s videos on YouTube.

The following pictures illustrate the step-by-step make of the tuners.

Aluminum “U” profile is 8x8 mm (external dimension). Wood tips are 6x6 mm.
Everything assembled with cyanoacrylic glue.

Note: drill a hole diam. 5 mm into a 6x6 wood tips is not easy, but anyway not impossible.

This are M5 wing nuts; one wing is already drilled to accept the string.

A Dremel is very useful to cut one wing, then a file will used to shape the wing nut in the desired way.

To have a good grip, the first idea was to us this units with a knurled outer diameter.

After some tests, I realized that it was better to use a simple tool to tune the strings – shown later on.

Now is time to assemble the tuner.

Self-locking nuts are used.

The change from the knurled cylinders to the allen screw head.

A little bit of silicone grease has been applied on the M5 threaded bar (grease used to lubricate bicycle bearings); this shrewdness reduce a lot the friction, improving the quality of the tuning.

In the following picture is possible to see how the strings are fixed to the tuners.

A small portion of insulation from electric cables is used to protect each string.

To make a carbon fiber part, you need a mould.

From my previous experience in aeromodelling, I have the know-how in making foam parts cut with a hot wire. There are thousands of tutorials out there to learn how to do. I have used this technique to make the mould.

The trick that I suggest is due to the conical shape of the body: just one template is necessary if the hot wire is fixed on the vertex of the conical surface. The other tip of the hot wire will pulled by hand during the cutting, using the single template as reference.

The following is the result of the cut: male and female moulds.

In the following picture some additional tricks can be highlighted:

• Two wood stripes are glued to the mould in order to end up with more carbon fiber in these areas
• Double-sided tape is applied to fix an old radiography (yes! – old radiography are smooth, flexible and for free) in order to have a nice smooth surface on the outside of the body

Also for carbon fiber parts there are thousands of tutorials.

For this simple components I didn’t use vacuum, just carbon fiber layers in between two mylar films (if you don’t know where to find mylar films, florist shops can be a great source: transparent sheets used for bouquets are generally suitable for the purpose).

Please note that the raw component has a sort of “omega” section; the flat lateral sides will help for the next building step.

Now is time to refine the carbon fiber component.

The raw component was rested on the worktop and then slid horizontally against the rotating blade of the Dremel. Fixing the Dremel at the proper height it has been possible to obtain a perfect horizontal cut.

Perpendicular cut at both ends of the body.

Trimming of the sides of the carbon fiber body.

Warning; carbon fiber dust is not the best for your skin, eyes and lungs. Protect yourself in a proper way.

At the end you will end up with something like this.

Here is where the strings are fixed.

Some electrical components are suitable for this function.

The internal metal parts are glued into slots cut in a hardwood stripe.

Finally, everything is glued on the internal surface of the top-plate.

Top plate is 4 mm plywood. A trapeze-shaped piece.

On both long sides a 2x4 mm wood stripe has been glued to the internal surface of the top plate in order to have a better joint between the carbon fiber body ant the top plate itself. Here epoxy glue has been used.

The fretboard and the bridge are from e-commerce: so cheap and ready to use; it makes no sense to make them. Bridge includes a piezo pick-up.

Also here in the head block, a small portion of insulation from electric cables is used to protect each string from the screws used to clamp the strings. The small portion of insulation from electric cables is hidden inside the holes where the strings go through.

As said at the beginning, the first solution used where the strings bend tight to reach the tuners was not working properly. So I decided to eliminate the aluminum tube and to use roller bearings (they are probably used for DIY 3D printers, really cheap and with the proper size 12x3x4 mm - O.D., I.D., W).

The supports for the bearings are 3D printed parts.

Again: 3D CAD concept, then real part.
Of course for 3D printing a .stl file is necessary … and 3D CAD is the only way to have one …

In these pictures it is possible to see also the jack of the piezo pick-up.

And this is the final result.

I like it!