Waking Spirit Productions
Vance Pennington - Flute Maker
Koko Waking Spirit Flutes

Frequently Asked Questions
Bore Sizes


How relevant is the bore size to the key (scale) the flute is being created to play?


Bore sizes are critical! Take for example an F# flute. This tuning requires a fundamental note of F#4 up to at least the highest note of its basic or primary note of G5. Whereas a 7/8th inch bore will basically suit the fundamental F#4 a more appropriate bore size for the G5 is 3/4 of an inch. In this instance a bore size needs to be used that will accommodate both the F#4 and the G5 perfectly. In order to do this the flute maker needs to calculate a bore size that will accommodate both the F#4 and the G5 as well as higher notes that can be played by a quality 1.4 octave flute. In such an instance a realistic bore size will be between 7/8ths (.875) of an inch and 3/4 (.750) of an inch. A bore size of .8043 is calculated to be the most suitable.

Creating a flute with an accurate bore size of .8043 requires the flute body to be created in two halves so that the routed bore can be accurately established. No drill manufacturing company creates a standard .8043 drill bit so creating a flute in two halves is an important aspect of a quality instrument.

The reason why such a bore size of .8043 should be used for an F# flute is very simple. 'Recorder' makers, for example, understand the principals of relevant bore sizes and use a conical bore for accuracy. This allows the lowest note, that is formed in the larger part of the conical bore, to form correctly right up to the highest notes that form in the smallest part of the conical bore. The Native American Flute does not have a conical bore and so an acceptable bore size needs to be calculated so that the lowest and highest notes all play accurately. This is often more/less than a standard drill bit size. Over sizing a bore can produce many problems with a flute when it is played. 'Drop out' is a classic example when, during playing a tune, the flute stops playing and then recovers again. This is due to the 'node' (that is formed inside the flute when it is played) not being able to establish itself correctly because the bore is too large. This often explains why 'Mega Bore' flutes do not play too well and are often 'noisy' due to excessive 'white noise'.