OK so now we actually begin making! But – we need to know what we’re going to make first. This depends on what key we want the flute to be in. The keys are usually referenced with “Middle C” on the piano, also called “C4”. A C4 flute would be an extremely low pitched flute and very large… but I’ve heard of flutes going down to F#3. The highest these flutes seem to sound nice is about D5 or E5 – above that they sound shrill and un-musical. (Not to mention being difficult to make!). (The number changes at C, by the way; the next note after B3 is C4).
The key you want determines the bore size you should use – because of lots of boring old (absolutely essential) physics. S0 – if you want anything between A3 and B3, you should be using a 1.25″ (32mm) diameter bore; C4 up to about E4 use 1.125″ (29mm); Eb4 to F4 use 1″ (25mm); F4 to Ab4 use 7/8″ (22mm); G4 to Bb4 use 3/4″ (19mm) and B4 to E5 use 1/2″ (13mm). There’s some space to vary this but the hole spacing becomes either very tight or very wide; for instance I have made F#4 and F4 flutes with a 19mm (3/4″) bore.
Of course – the bore size determines what size of wood to use for your “Blank” – let’s concentrate for the purposes of this “course” on a flute in “G” which we will make using a 3/4″ bore… 19mm. From now on, I’ll use mm because they’re much easier to write and they’re more granular than fractions of an inch. I choose this size as it’s a good middle ground and is “easier” to make.
For this flute I use a “blank” of two pieces of wood, 600mm long and cross section 34mm x 17mm. This is a nice size which gives a good strong glue bond down the bore and also gives plenty of error room when hacking and chopping bits of wood off! 😉
So that’s your task today – find and prepare a flute blank: for grain matching, it’s best if your two pieces come from the same double-thickness piece of wood. You’ll need a planed or sanded finish, which ensures they’re straight and flat. This is best done by your supplier, especially if you’re not an accomplished woodworker – it’s not an easy job for a beginner.