You mean increasing the bore. You’d drill the bore the diameter of the smaller exit hole at the foot, then ream out to the larger diameter at the head end of the flute. This would probably involve custom made reamers.
You can look at various flute making sites as well as recorder making sites for what other makers do. Here’s the procedure I like. Drill an undersized pilot hole the length of the blank. Then step drill in sections to remove additional material while not exceeding the final bore size at any point. Use the pilot hole as a guide for the step drills to keep things on center. You can use as many steps as make sense for you. Then use your reamer to finish the bore to size. Most flute and recorder makers will utilize self-made reamers but if you can find appropriately sized tapered reamers you could use commercially made cutting tools. Building the flute in sections can help too, IMO. Luc Verhoven has a good website which illustrates his flute making procedures. He shows how he shapes his tapered bores there.
Quenas aren’t usually conical. They have a narrowing on the end (bamboo node or stuck-on washer-like disc) to narrow the bore and simulate the effect of a conical bore.
True, traditional Quenas are made to simulate a conical bore by making a reduced bore end hole in a natural bamboo “node”, but a professional instrument would require a tapered bore for acoustic superiority.
I suggest drilling a 1/2" bore first and then using a tapered “Reamer” (shell reamer) to expand the top of the bore to 3/4". This can be done with a open ended steady rest on the lathe. I like to make my bores in 2 halves on the router table and then epoxy the 2 halves together for an invisible seam. I then use my custom set of reamers to ceate the taper I desire. Any home machinist can make a set of these for you cheaply. There are also plans for reamers in Trevor Robinson’s book “The Amateur Wind Instrument Maker”. Here is a site page from the Recorder Homepage on Reamers…
a professional instrument would require a tapered bore for acoustic superiority.
Fedoggie and Thomas… Your information / link was very right on… It sounds like a good direction to go. Yes, I am working in two different directions, one with a straight bore and a professional taper bore instrument. Much like Hoza and Rueda.
There are lots of Custom Reamer Companies out there… Has anyone ever had a Custom Reamer made or made one yourself ? Any suggestions ?
I have also looked through a couple tooling catalogs online for stock tapered reamers that would work for flute making and you can get pretty close to a proper flute bore going that route. That’s just pricey for me as a hobbiest maker at this point.
I’m a Journeyman Machinist with a degree in Mechanical Engineering. I have a few small Mills, but I make my own Reamers on a CNC Hobart milling machine. I suggest you head to your local High School Metal shop and see if you can con someone into making a couple reamers. You might also try a local Machinist Tech School and ask a student to make one for you. Of course, you’ll have to pay them, but it won’t break the bank. I personally have never found a commercial reamer with a long enough taper for making woodwinds. There are also some fancy Router Table jigs for making tapered half-bores. Do some Googleing…(?)
As far as I can see, there is nothing in the mathematics on that page about quena designs that addresses the flat second octave issue. They just say if you leave the end plug off you can get the first octave dead in tune. I think we already knew that.
Conical bores eliminate the flatness in the second octave by shifting/compressing all the antinodes in the second octave closer to the voicing, this also increases acoustic backpressure. This is the reason Recorders are well in tune in the second octave. Cylindrical bores suffer from flatness because the aircolumn extends farther out the bore end due to increased aircolumn velocity.
You can address the flat second octave by using a different taper toward the mouthpiece. Recorders do it by having a cylindrical bore at the window, then narrowing toward the far end. Flutes, which have cylindrical bodies, have head-pieces that narrow toward the top. It is the difference that does the trick, not whether the body is conical or cylindrical.
I am in the process of making a Reamer based on the information you all have provided… But to save time I would just as soon buy a Custom Made Reamer … Has anyone ever bought a Custom made Reamer ? Any recommendations as to a good place to buy one.
Since most makers of wooden whistles use a straight wall bore you may not get many more responses on this forum. You might want to ask on the C&F flute forum or do a search on the yahoo flutemakers forum. It is more customary to have a tapered bore on an Irish flute. You could look at this post from the flute forum and see if it leads you anywhere.
I don’t know the key in which you are going to make the quena, G is rather common, but most Irish flutes are going to be made in D. And while there are obviously G, F, Eb, Bb and C flutes being made most makers will have made their own reamers I would think. And for the issue of bore length most will have reamers made for each section of the flute. So I don’t know what providers of reamers you may turn up but who knows. Keep us posted in any case.
I make most of my conical bores using Metal Spinning lathe techniques over a wooden mandrel of the proper shape. Annealed Brass and Copper tubing can be spun down over a mandrel to a perfect conical shape in just a few minutes. Not everyone has a lathe to do this though. I doo my spinning on a small lathe with hand spoons, but here is an example of commercial “flow spinning” that will give you a good view…
How about just installing a plastic wedge like Doug does for his cylindrical Tipple flutes? Seems to work well. But not sure if this method would work for an end-blown flute.