Making the ukulele fretboard
Traditionally, these are made from dark exotic woods, so I figured a dark fretboard would look much better. So I used some black acrylic artist paint to stain the board black.
Spacing out the fretsThere are various tools on the web to help you calculate the layout for the frets for guitars or ukuleles. But it's so easy to work these out with a pocket calculator that it's hardly worth the time to learn how to use one of these tools.
I start by determining the "scale length" of my ukulele. The scale length is the length of free string between the bridge and the "nut" at the head of the ukulele.
For my instrument, the scale length came to 45 cm. The math for working out the frets is easy as long as you measure everything from the bridge, not the nut. So I placed my tape measure so that it starts at the bridge position. With my scale length of 45 cm, I put the end of the fretboard (where the "nut" will go) at 45 cm.
Starting with the nut, the free string length for each successively higher toned fret is the twelfth root of one half as much. That is, if the nut is at 45 cm, we multiply 45 cm by 0.5 raised to 1/12. So 0.5 raised to one twelfth is 0.94387
I use a calculator with the "constant calculation" feature. Most five function calculators have this feature, but most scientific calculators do not, although this one does. "constant calculation" means that the calculator will repeat the previous operation when you push "=" again.
So start by multiplying the 0.94387 times itself. Then enter "1" and push "=". If the display now goes to 0.94387, you are good to go.
Now enter the scale length on your calculator and push "=". This should give you the position of the first fret, as measured from the bridge. Mark this position, then push "=" again, and you have the next fret position. Each time you push "=", you get the next fret position.
I marked all the fret positions on a strip of wood. On close inspection, one of the tick-marks looked slightly out of place, so I re-entered the scale length in the calculator and kept pushing "=" again until I got to this position. I had erred by 1.5 mm when I marked this position.
I clamped this block onto my fretboard. By pushing the saw up against it, I was able to use it as a cutting guide as I cut the fret slots with my dozuki saw. The saw isn't any special saw, just a saw with a very fine kerf.
I had a strip of wood on either side of the fretboard that I was cutting, and I cut each slot until the saw cut into the strip on either side. That way, I could be sure that I cut deep enough, but not too deep.
Installing the fretsI ordered the fret wire, along with tuning heads and strings from Stewart MacDonald. The fret "wire" comes in 2' (60 cm) lengths, and is cut to length as it's used.
It took some experimentation to find a reliable method of getting those frets in. If you just try to push it in straight, it usually tips over left or right before it actually goes in the slot, or at least that was the case with the narrow slots I cut with my dozuki saw.
The method I ended up using was to hold one end of the fret, and squish the other end of it into the slot with pliers. By only squeezing it in at the end, I still had good control of it with my fingers.
I put some pieces of UHMW tape on the jaws of my pliers to keep them from marking up the frets or the wood.
I could have worked it part-way across with the pliers, but that would have caused some sharp bends in the frets. So instead, I used a block of wood in my vise.
I think the slot from the dozuki may have been on the narrow side, so the frets were quite hard to get in. But by working the fret wire in like this, I didn't end up with any kinks, so I think this method is better than hammering them in.
I should have used a harder piece of exotic wood to squish the frets in with.
I also noticed a little bit of damage on the fretboard on the side I started all my frets on. So it might be a good idea to taper the fretboard after inserting the frets so that slight damage on the edge gets cut off.
I then stained the edges of the fretboard to make it look like it was all one black piece of material.
Glue is a lubricant, and when gluing two flat surfaces together, it often causes the pieces to slide out of alignment. So I drove two finishing nails into the neck and cut them off to stick out about 1.5 mm from the surface.
I then lined up the fretboard and pressed it onto the nails. This resulted in two small divots in the back of the fretboard to keep it aligned during gluing.
See also: Pat making the fretboard
Next: Finishing the assembly