WHY POHAKU
WHY POHAKU?
This section, ‘Why Pohaku’ attempts to explain and illustrate what makes Pohaku ukuleles as good as, or better than other choices.
Mostly it is attention to every little detail which is difficult to document, but these are well-thought-out instruments that are executed with a high level of craftsmanship. I’ll explain some of the details where Pohaku goes the extra effort to bring you a super quality instrument.
An instrument playing in tune with easy playability is a major component, so we’ll start with what makes killer fretwork. Everything is important in instrument building, but the neck / fretboard assembly is perhaps the most important part. It’s what a player holds onto and chooses which pitches to play. It is the command center, so to speak.
FRETWORK
50s and 60s Martins and Gibsons often have amazing set up and playability, and one of the main things the masters did was add relief to the fretboard and frets. These instrument were so much better set up than the typical Hawaiian instruments that simply have flat milled fretboards.
So I spend the time to not simply flatten the frets as most makers do, but I add relief to the frets with a detent of about .005” at the 7th fret and the rest of the frets relieved in a graduated curve. The strings are set to be .016” at the 1st fret and .100” at the 12th fret. I never have string buzzing issues.
Adding relief is an accurate and laborious process that very precisely adds a gentle relief to the length of the fretboard.
Adding Relief to the Frets
Protruding fret ends are annoying and are caused by the tang of the fret protruding out of the side of the fretboard. This can be caused by poor construction and not well dried fingerboard wood.
The wood that I use has been drying for years. Importantly, I cut back the tangs on the frets and afterward fill in the gap of the fretboard slot. The fret ends are each carefully rounded and polished.
INTONATION
Intonation is super important. Firstly, the fret slots spacing needs to be carefully calculated and carefully cut in the fretboard. And then the bridge has to be in the right place. All strings need some compensation to play in tune.
Here is the system I devised and use to place my bridges in a sweet spot, so the intonation of the instrument is as precise as possible. This description of my bridge placement method is from an article I wrote for the Guild of American Luthiers Magazine, “Ukulele Scale Intonation.”
BRACING
Soundboard bracing has always been thought to be magical and the key to an instrument’s good sound, and that is true to an extent. Over the years I have braced in most every conceivable way and I have concluded that most bracing patterns can sound good if they’re executed correctly and they have somewhat different characteristics. For the last decade, I’ve settled into using only ladder bracing.
I like ladder bracing because:
A characteristic of ladder bracing is an instrument with sharp attack, good volume and less sustain. Punchy sound is a good characteristic for a ukulele! This is my most important reason.
With thin ukulele soundboards, the horizontally placed ladder braces don’t show transparently through the thin soundboard. Fan bracing and other braces that go vertically or diagonally with the grain often can be slightly seen and felt as a slight bulge in the soundboard, this I call ribbing because it looks under-fed.
The ladder bracing pattern doesn’t interfere with the string through bridges where the string hole goes through the soundboard and ties in a knot.
Ladder Bracing - Top
In my building, the bracing stiffness gets adjusted three times during the build. The braces initially get glued onto the soundboard at full thickness. Then they get thinned down to where I like the stiffness of the soundboard & braces.
Once the soundboard has been glued to the body, the braces get thinned further because the body has stiffened to top.
And lastly, once the bridge has been glued on, a final adjustment of brace thickeness / top stiffness gets done as attaching the bridge has the same stiffening effect as adding a massive brace to the top.
HUMIDITY CONTROL
Wood, especially thin pieces of wood, will shrink and grow with humidity changes. Think of that piece of paper curling up on your desk on a humid day. It’s important, and it’s an industry standard to build fine delicate wood objects such as instruments in a humidity controlled environment. You don’t want to glue together something on a humid day and then glue something else on the next day when it’s drier because it will build stresses into the instrument and the instrument wants to be built in a relaxed state. So building in a humidity controlled environment is important.
Once an instrument has exited the shop it goes out in the world where it may be dry or it may be damp. If the instrument starts life at a midpoint humidity (ideally close to 50%) then it can move to a humid climate or a dry climate and have a much better chance of not being affected and having nothing undesirable happen to the delicate construction.
I have humidity control in my shop and I use scientifically accurate gauges to monitor the humidity. I also have a dedicated 50% humidity room which my woods live in for years and instruments stay in throughout the construction process.
CURVED BODY BLOCKS
It’s just another one of those little things that adds to the instrument. Technically, an instrument cavity wants to have many different lengths inside of it. An instrument cavity is an acoustic Helmholtz resonator, and guitars/ukuleles are shaped as they are to provide an infinite number of lengths for the sound waves to amplify. It’s basically an acoustic amplifier that doesn’t need to be plugged in. Each note has a different length sound wave and as each sound wave finds a sympathetic length in the cavity of the instrument it will be amplified. Too much of the same dimension will over-amplify a certain note, which is called a wolf tone. Hence, curved head and tailbacks probably help the sound by eliminating some spots for wolf tones.
Arched Back
BACK PLATES ARCHED
The backs of all Pohaku Ukuleles are arched along both axis, giving somewhat of a bowl shape to the backs. This strengthens the sound amplification by providing different resonating lengths inside the instrument for sound waves to find a sympathetic amplification length.
The back horizontal radius varies from 36” to 48” radius on the different instruments. Ovation guitars with their curved backs say that this shape helps to bounce the sound out of their sound holes. I’ll roll with that explanation too. The design of the Pohaku ukulele is a variation of a Spanish heel construction method and the backplate also sets the neck angle as the ‘button’ on the back glues to the heel of the neck setting the neck angle. Violins have a similar construction.
Each arched back brace sets onto uprights glued onto the sides of the instrument. This makes a box shape out of each back support brace and adds stiffness to the sides of the instrument.
GLUING
Gluing may sound simple, but good gluing technique is important.
Pohaku has a gluing caul for nearly every gluing step, and each caul is made specifically for one step of construction, and there are cauls for all of the instrument variants.
Gluing Cauls
Floating Mortise Joint
NECK JOINTS
There are a different ways to make a neck joint. It’s really the biggest main joint in the construction of the ukulele, and it wants to be as good as one can get it. I see lots of poor fitting necks with the neck's outer edges hovering away from the body, which I find amateur.
A neck joint has to be a really good fit of the concave neck curve to the convex body curve. It has to look good and be strong. The neck also has to be straight and centered. I use a glued spline method, which is a floating mortise joint. I also use a laser line to know when the neck is absolutely straight. I have some well-made jigs and fixtures to help me achieve this important and difficult task.
NUT SLOT
Crisp solid nut slots hold the nut exactly where it should be. A nut wants to fit very well. Pohaku nut slots are accurately made. A nut that doesn’t fit perfectly may cause poor intonation and are a source of buzzing.
Nut Slot
BRIDGES
Pin-less String-Through Bridge
Bridges need to be well made. I’ve gone completely away from tie on style bridges and use the pin-less string-through bridge on the larger instruments and the traditional slotted bridges on the small delicate instruments. Pohaku bridges are accurately and thoughtfully made.
Slotted bridges are cut with a variety of slot widths so that strings will never fail and pull thru the one size fits all slots.
Likewise, the pin-less bridges use a variety of different size holes to accommodate the different size strings that an instrument is strung with.
The pin-less bridges eliminate any chance of string ends poking the player’s wrist, and they look elegant. I always make them with two different wood species that are designed to complement the instrument the bridge is chosen for.
Also because the string knot bears against a hard maple bridge patch on the back side of the soundboard, the strings are no longer trying to pull a bridge off a soundboard. Instead, they are transmitting all the string energy into exciting the soundboard and making sound.
IN CONCLUSION
Add to all of these features added with super care in construction, and a very unrushed building schedule contribute to making excellent ukuleles.
Thirty thoughtful years and over seven hundred ukuleles of experience doesn’t hurt either.
I still to this day strive to make each instrument well and make each instrument a little better than the last one.
There are still small changes happening that I implement that allow me to continue improving and challenging myself and create the best instrument possible for youth enjoy and one that will last and be cherished for years..