Also called a sopranino, this tiny ukulele is about as small as they get.  With a scale length of 280 mm (imagine a mandolin starting at the 3rd fret) the piccolo is tuned dgbe, an octave above the baritone uke, or cfad, a tone below that.  It is much lighter built than the factory instruments you may have seen and has a more full-bodied sound, in spite of the high pitch.  All this is achieved by carefully selected and graduated tonewoods, plus a single Portugese style back brace as seen in the first Hawaiian soprano ukuleles.  Unlike the rigid original back braces,  my laminated cross grain contact brace is slightly flexible and gives the sound a real  “pulse” as well as preventing the back cracking with humidity changes.
 

This through-the-soundhole shot shows the laminated transverse back brace on the piccolo ukulele back.

Arched Soprano back

SOPRANO

What is known as the soprano ukulele nowadays is often called the “standard” ukulele in Hawaii.  This small, short scale instrument was the original ukulele. It is tuned GCEA or a tone higher at ADF#B.  The model I use is copied from a Kumalae ukulele from the 1920s, which in turn seems to be a close replica of the original ukuleles made popular by Manuel Nunes who was one of the first ukulele makers in Hawaii.  Nunes, a cabinet maker and younger brother of Madeira’s most famous luthier, Octaviano Nunes, is said to have adapted the small Portugese instruments, machete or braguinha and the rajao to make the first ukuleles.
Utilising very similar body dimensions and scale length, my soprano ukulele is a little different to the old original instruments.  Like them, it is very lightly built but has some differences which enhance its sound, intonation and longevity.....
An ebony fingerboard
A compensated bridge for correct intonation
“Peghed” geared tuners for ease and accuracy of tuning.
A cylindrical arch in the top which allows for a finer graduation of the top thickness, making the instrument more responsive and helps prevent cracks due to humidity variation.
A unique arch in the back, formed before the back is joined and reinforced by a single lightweight arched laminated brace running along the seam.  This gives the back the ability to both support lower frequencies and also enhances projection of sound in all directions.  As there is no transverse brace in the back it can handle shrinking and expanding across the grain with humidity fluctuations.  This feature is my own design and is currently unique to my soprano ukuleles only. It produces a very rich, rounded tone for such a small instrument and a wonderful rhythmic “pulse”.

Laminated back arch brace

CONCERT

Why is this slightly larger ukulele called a “concert” ukulele?  One suggestion is that the longer, 15” or 380mm scale length gave the instrument more sustain, more frets, and enabled a more sophisticated repertoire in what was called “concert pitch” the C tuning we use almost universally nowadays - GCEA, two semitones lower than the ADF#B tuning often employed on soprano ukuleles.  By the time the concert ukulele appeared, ukulele making had become partly the realm of big mainland companies.  There is a reference to Sam Kamaka, who had worked for Nunes in the ukulele’s early stages, inventing the concert ukulele.  The Martin guitar company started producing concert ukes in 1925.  They caught on.....amongst quality ukulele makers, concert ukes are the most popular.  One very fine player I know prefers concert size simply because there is more room for his fingers.
I use Peghed tuners for preference on this model, but the string tension is low enough to use good quality friction pegs.  There is more about tuners on the options page.

TENORS

The tenor ukulele started to appear in the late 1920’s.  By this time ukuleles were being made by the thousand in both Hawaiian and mainland USA factories.  Perhaps the “bigger is better “ notion was part of this and perhaps also the increased sustain and low end response of the concert uke was catching on and players wanted to take it a step further.   At any rate, with its 17” (432mm) scale and larger body, here was a ukulele which could support a low G string in the GCEA tuning.  This may have made more logical sense to guitarists as well.   
As the factory era was well and truly established in the mid twenties, most concert and tenor ukuleles show the typical characteristics of factory assembly.  They are much too heavily built.  What I have done with my instruments is take them back in the direction of the original  Portugese / Hawaiian instruments.  They are lightly built but strong in the right places and sensitive in the right places.  They have sophisticated but simple soundboard bracing, which is tap tuned and optimised for each individual instrument.
The original configuration of the tenor ukulele, like the concert and soprano, was with the 12th fret at the body join.  This put the bridge nicely in the middle of the lower bout, an arrangement which suits gut or nylon string guitar family instruments best.  For this reason, my standard “traditional” tenor ukuleles are configured this way.  The sound is strong and balanced. (Picture at left).
As steel string guitars evolved in the 1930s to 14 fret necks for easier high note access, the ukulele followed that trend shortly after. This did little for the sound, but became the standard configuration.  Ukulele virtuoso soloists tend to use these 14 fret  tenors, often with cutaways, as their instrument of choice. 
My Solo Tenor model  (picture at right) is the result of a considered re-design of the body to allow for a 14 fret neck with the bridge kept nearer the centre of the lower soundboard than it would be if the neck were simply shifted two frets out.  It also has a bridge design and bracing pattern which enhances the response higher on the A string, a feature appreciated by solo players.  Generally speaking the sound is more treble / midrange focussed than my standard tenor.  Like all my ukuleles it is lightly built.  There are more design considerations on the Options and Design pages.
 

BARITONE

The baritone ukulele was first made in the 1940s.  It has the same tuning as the four highest strings on a guitar -DGBE.  The scale length of my baritone is 515 mm (20.275”).  It has a 14 fret neck, but has a well placed bridge due to the body size.  Although the tuning is similar to the guitar, the sound is very ukulele, due to the tonewoods, the bracing design and voicing and my lightweight build.

ACACIA BASS

After a long period of prototyping, this baritone-sized bass ukulele of my own design has  been unveiled.  It features Aquila Thundergut strings, Hipshot alloy tuners, a Shadow acoustic bass pickup, MiSi preamp and a special internal resonator which enriches the low end response.  On stage,  through a good bass rig , this tiny bass delivers a very double bass-like sound.