A ukulele fretboard (also known as fingerboard) is usually specified by it's scale length, the width at the nut (0th fret position) and the width at the 12th fret position. For a standard tenor ukulele they are 431.8mm, 35.7mm and 46.0mm respectively. A typical fretboard normally has 18 or 19 fret slots for inserting the corresponding fret wire. The position of each slot (d) as measured from the nut is calculated using the following formula:
d = s - (s/(2^(n/12)))
where s is the scale length, and n is the fret number. Note that the 12th fret position is half of that scale length. We could easily customize a slightly different scale lengths for a similar body design.
The top surface of the ukulele fretboard may have a radius as normally found in many acoustic and electric guitars. The radius facilitates a more comfortable bar fingering when playing the instrument as it follows natural human fingers in a relax situation. However the radius fretboard renders additional work on the part of the builder.
Other normal features include fret markers, side binding to hide the slot's end, and other optional adornments.
The overall thickness of the fretboard varies between 4mm to 6mm. It is popularly constructed from woods that are stable and strong such as ebony or rosewood. Other woods such as maple may also be used for the construction of a fretboard.
Constructing a complete fretboard is a bit tedious process.
Starting from a fretboard blank, people have successfully employed CNC router to help construct the fretboard. The product will be more precise and reproducible. The method we are employing here is to write CNC codes namely the g-code thus avoiding the use of CAD/CAM software for the design and g-code generation. To ease the development, rather than doing it as a continuous process, we break the process into several small tasks. Each task may be applied independently. For example, fret radius may be used for fretboard that is already been previously slotted (with a fret saw). This will help in the construction as each module may require a tool change with different type and size of router cutting bit.
