Step 1: Bamboo Flute: Transverse Traditional
First of , before any construction can begin, remember: Safety First! Though making these instruments doesn't require many large, dangerous power tools, be aware that accidents can still happen. Be sure to wear saftey glasses (fig.1) and never touch the blade or cutting edge of a tool that is powered on. I am only responsible for teaching you how to make a rockin' musical instrument, not for making horrendous injury.
With that out of the way, let us begin constructing our flute.
Preparing the bamboo:
First, find a nice piece of bamboo. You are looking for one with a mostly rounded body of moderate diameter, without any suspicious holes or splintering, injured patches (fig.4). To prepare the bamboo, remove all the branches by using a hacksaw (fig.2). It is a good idea to sand down the notches from which the branches were cut to create a more sleek instrument (fig.3). Also, note that the piece of bamboo you chose for your flute must have at least one node, which will serve as the "cork" that is situated close to the embouchure, or "blow hole". This node must be solid and not have any bumps or holes on the outside or the inside of the bamboo, as this node will be crucial in achieving proper tone.
Making the cut:
From the node that you have selected to serve as the "cork", measure 2 cm out (fig.5) and mark a line there with a pencil. This will be the one end of your flute, nearest to the embouchure, separated by the node. Use a hacksaw and carefully cut along the line all the way down through the bamboo. This first cut will be rough (fig.7), and it will take some sanding (fig.8) to make it pristine and smooth (fig.9). This cut has revealed the node, and will give us some Idea of what the inside of our flute-to-be looks like. As we will need to know the inner diameter and the wall thickness of our flute for calculations and cutting the embouchure, measure them now using this hole (fig.10).
The general rule for the placement of the embouchure is that it's center should be "one inner-diameter length from the cork". Measure one length of the bamboo's inner diameter from the node (fig.11). Mark this place with pencil, as it will be the center of the embouchure. To calculate the proper diameter for the embouchure, among other measurements, use the Flutomat, an absolutely brilliant Java calculator for flute-making (fig.14). Input your flute's inner diameter, wall thickness, and select a key for the flute to be in. The app will calculate the exact placement and diameter for the embouchure and the other six holes that complete the 7-note western scale. Once Flutomat has given you the proper diameter for the embouchure, begin to drill. Clamp the bamboo down firmly with the embouchure mark face up. Begin by drilling at the center using a small drill bit. I first used a 2mm bit to start the hole, then progressed to a full centimeter with about 3 other bits in between. Figure 12 shows the drilling process, with the bamboo clamped down and the drill carefully but deliberatley being thrust through the bamboo. It is EXTREMELY important that the drill is perfectly perpendicular with the bamboo, that the cut is deliberate and forceful (no resting on the pre-cut hole), and that the drill is held steady and sure. Without applying these guidelines, the bamboo will rip, splinter, and crack. In general, BE VERY CAREFUL. When the hole is cut to the proper diameter, feel free to file and sand it to make it smooth and perfectly round (fig.13). Test the embouchure and make sure your get a familiar, mellow, "flute-like" tone. If further adjustment is needed, you may need to use a file to bevel the playing edge of the hole (opposite the player) so it is at a downward slant away from the player. My flute did not require this alteration, and if you feel like no adjustment is needed, play it safe and don't make any.
Making the cut, Part II:
Flutomat gives the length between the edge of each hole and the open end of the flute, so to cut this end, we must measure out the designated distance from the embouchure, the only hole we've cut so far (fig.15). Once you've measured the correct distance, mark it with a pencil (fig.16) and cut through the bamboo as described earlier (fig.17). Sand the opening down and clean up the gut with files and sandpaper (fig.18,19)
Knocking out nodes:
Chances are that while making your flute, you have chosen a piece that will have more than the one node that is serving as the cork. This node has to be "Knocked out" and completely gotten rid of before the flute can make any sound at all. The method I used to knock out the node was using a piece of rebar that fit the inside of the bamboo fairly well, and tapped it multiple times with as sledgehammer until it broke the node out from the rest of the bamboo. Be warned that THIS CAN BE EXTREMELY DANGEROUS. I tried this method a second time and the bamboo split right in half. Instead, I would suggest using a drill bit that fits loosely into the diameter of the bamboo and drilling it through. You need to push a little more to drill out the node, but it will go through with a much smaller chance of damaging your flute. Figures 21-23 cover how I removed the nodes with rebar, though it isn't suggested.
At this point, your flute should look like the one pictured in Figure 24.
Believe it or not, this is the easy part! The Flutomat calculator gives the diameter of each tone hole and the length between them and the open end of the flute. Measure the given distance from the end and mark it lightly with pencil (fig.25). Keep in mind that this mark indicates the edge of the tone hole, not it's center, so before you begin to drill make a mark one hole radius up from the original mark. This will be the center of the hole. Now, like the embouchure, each hole must be drilled in successively larger drill bits. I usually started each hole with a 2mm bit (fig.26), then moved up to the calculated diameter (fig.27). After each drilling, with each size bit, I cleaned up the cut, removed any splinters, filed it circular with needle files and took great precaution to prevent cracking. Also, be aware that some parts in the bamboo are thinner than others, usually where branches are growing, and are thus more susceptible to breaking. The first hole I drilled (fig.28) was over such a spot, and was very close to a node, but this didn't seem to affect the tone at all. If you find your hole e is over a node, don't fret. Try to drill it as best and as carefully as you can, and clean up the node on the inside really well. I continued to drill all six holes (fig.29-33) and kept them in a straight, even alignment, though technically, the placement of the hole around the outside diameter of the bamboo is not as relevant as it's distance from the end of the flute. Once you have that sixth hole cleaned up, YOU'RE DONE! Now go and enjoy your instrument (fig.34-37)
To clean up my holes, I decided to try and burn away the splinters using a candle (fig.38,39). This worked... somewhat. It left my flute with the brownish gold blotches around the holes that you can see in the first picture. Some people try to "jump-start" the gradual fade from green to gold by taking a blowtorch to the surface of the bamboo, which changes it instantly. This can also be blotchy if not done correctly, and you can damage your instrument. For the average bamboo-flautist, I would suggest skip;ping this.