Some Successful Designs for Inexpensive PVC Flutes

Introduction

Here are some notes on making flutes from inexpensive plastic pipe along with successful "recipes" for the hole diameters and locations for a couple of alternate D flutes made from Schedule 80 PVC pipe, a G flute from 1/2" Schedule 40 PVC, and a little D piccolo or fife made from 1/2" CPVC pipe.

General Notes on Construction Technique
For all the designs below I cut a chunk of pipe off square (on both ends) with a (manual) miter saw. I draw a pencil line straight up the pipe using a chunk of aluminum channel shelf bracket support from the hardware store as a guide. I hook a steel tape measure on one end of the pipe and mark the hole distances on the centerline. Where I indicate an offset up or down for ergonomics, I wrap the steel tape around the pipe as guide, draw a line at right angles around the pipe and measure up or down from the centerline as indicated. Moving the holes off the drawn centerline makes them vastly easier to reach (although a D flute is still a challenge for small hands). Once all holes are marked I center punch them on the mark and drill a 1/8" starter hole.

I use a hand-held electric drill - a drill press might be better. When you are drilling large holes make sure you have a firm grip on the pipe! Standard twist drills will work pretty well for most of the holes but a 1/2" forstner bit is nice - the 1/2" twist drill tends to grab and make a messy hole. The aggressive, fast cutting twist drills sold by many are too fast-cutting in soft PVC, especially large diameters - a more traditional, standard bit is better.

For the embouchure hole, the blown edge should generally meet the pipe surface at about 45 degrees and be more or less in line with the center of the finger holes. The interior of this hole needs to be as smooth as possible and the blown edge should be clean and crisp. I drill the embouchure 1/16 undersize and finish with a chuck mounted straight reamer to final size (reamers are not cheap but they are affordable) or a regular twist drill at low speed. Drilling a clean smooth embouchure is an art. I usually end up smoothing out minor imperfections with a sharp knife.

I generally remove flash around all holes with a sharp knife - I also use this to bevel the inside top end of the D flute so the cork will go in. Paring a little off the un-blown edge of the embouchure hole to bevel it saves wear and tear on your lower lip. DO NOT bevel the blown edge of the embouchure hole - leave it clean and sharp. Don't bevel finger holes either - a crisp edge helps your fingers find them and excessive beveling will change the effective hole diameter.

A little note: DON'T BREATHE PLASTIC SAWDUST! Experience indicates that you will NOT enjoy the experience. Clean up after sawing and drilling, and clean off your flute before playing it, including running a wad of paper towel up the bore.

Most importantly, don't hurt yourself. If you are accident prone, a little drunk, jittery or otherwise impaired DON'T MESS WITH SHARP OBJECTS OR POWER TOOLS. Take all the time you need and work carefully.

Here is a picture of the tools I use and some flutes I've made. Notice the TEE cork before and after cutting off the plastic knob. Reamers and forstner bit are below that, center punch and drills to the right of those. The pencil is lying across the aluminum channel I use as a marking guide and some dowels used for adjusting cork position and/or making wooden "corks" for smaller flutes. The odd cylindrical objects with holes in em are flutes.

"Cork" Materials and Placement

For a cork for the D flute (or any 3/4" Sch 80 PVC flute) I use a TEE cork from a bottle of jug wine (or get some new TEE corks from a home-brew shop) and cut the plastic knob off with a sharp knife. Wax the cork by rubbing it with a candle. Bevel the flute inside on the embouchure end so the cork will go in, and push the cork in flat-end-first. Use a dowel to push it down till the face is just above the embouchure. Adjust cork position to make third octave D, E & F# match an electric organ (cork position doesn't affect the lower octaves much). Positions I initially wound up with experimentally for the various pipe and embouchure sizes in described in the "recipe" tables below were all roughly 1 embouchure hole diameter from the center of the embouchure hole. I might recommend this placement as a useful rule of thumb for a minimum distance. However, recently I have begun to think that placing the cork somewhat farther from the embouchure hole, roughly 1 internal diameter from the embouchure hole center, makes the flute easier to blow and the tone a little clearer.

For a cork for flutes made from 1/2" Sch 40 PVC pipe, including the G flute described below, you can use 5/8" wooden dowel for a cork. The dowel should be a force fit and can be tapped in with a hammer although some dowels may be a little small and require a dab of glue to be held in place. For the G-flute described in the dimension tables below, a 1" chunk of dowel set flush with the end of the 16 3/4" flute will place the cork face in a good position.

For a cork for the D fife described below, I use 1/2" hardwood dowel and pure brute force in the form of a hammer. I cut off a piece of dowel 31/32" long and bevel one end of it slightly with a file or sandpaper. Stand the fife on end on a solid surface like a kitchen counter and pound the dowel in, beveled end first, until the wood is flush with the plastic.

A suggestion I have heard for making a "cork" that will fit the inside of any tube one happens to have handy is to wrap masking tape round and round a piece of dowel until the wrapped dowel is a good fit in the pipe or tube.  I haven't tried this but is sounds reasonable.

Fairly recently I acquired a "cork inserter" and a supply of wine bottle corks from my local home-brew shop.  I find this to be a dandy way of putting a cork in flutes made from schedule 40 pipe and plan to add some designs for such flutes to this page "real soon now".  I figure most folks aren't gonna rush out and buy a special tool just to make their flute, so designs that require a cork inserter can wait a while.

Know your Pipe
The hole sizes and locations given below are good only if you use the right pipe, the pipe specified for the particular design. The important things are the inside diameter and wall thickness of the pipe. The designs described work with the particular, types of standard pipe specified because the hole locations were calculated and tested for pipe with that internal diameter and wall thickness. So, how do you make sure you have the right pipe?

Schedule 80 PVC pipe is generally gray, while schedule 40 and other schedules are white. Not all gray plastic pipe is schedule 80, however. One foolproof way to tell what size PVC pipe you have is to read the printing on it. All the PVC pipe I have seen comes with a printed strip of information telling what diameter and schedule it is. Another way to check your pipe is to measure it with a vernier caliper - if it's within a couple of thousandths of the values given below then it will do.

Schedule 80 pipe is special heavy walled material. PVC schedule 80 is used because it's thick enough to allow it to be threaded and still retain enough strength to resist water pressure in plumbing projects. The D flute design below requires 3/4" (nominal) Schedule 80 PVC pipe. You won't find this pipe in every lumber yard and building supply store but it is available from stores specializing in plumbing supplies.

PVC schedule 40 is typically white and is quite common. It's available at Home Depot stores and most good building supply stores. Be careful to get Schedule 40 - thinner walled pipe of the same color is commonly used in sprinkler systems and is not compatible with the G-Flute design below.

CPVC pipe is different from regular PVC pipe. It is a sort of off-white, light beige material and is only sold in plumbing specialty stores. CPVC pipe comes in "copper tube" sizes (what I used) and also in standard pipe sizes (sch 40, 80, etc.) although nobody in Sacramento sells the latter. Pipe labeled 1/2" CPVC and measuring 5/8" outside diameter is the material you need for the D-Fife described below.

Standard dimensions of Schedule 40 and Schedule 80 pipe can be found in handbooks; CPVC pipe dimensions are a little harder to dig up (maybe my handbooks are just a little old). For calculating flute hole positions (which depend on pipe dimensions) I suggest using the following more-or-less standard dimensions, or measuring your pipe with a vernier caliper:

Schedule 40 PVC and Steel Pipe
Nominal   Outside  Inside    Wall
Diameter  Diameter Diameter  Thickness
1/2"      0.840"   0.622"    0.109"
3/4"      1.050"   0.824"    0.113"

Schedule 80 PVC and Steel Pipe
Nominal   Outside  Inside    Wall
Diameter  Diameter Diameter  Thickness
1/2"      0.840"   0.546"    0.147"
3/4"      1.050"   0.742"    0.154"

"Copper Tube" Series CPVC Pipe
Nominal   Outside  Inside    Wall
Diameter  Diameter Diameter  Thickness
1/2"      0.625"   0.469"    0.078"
3/4"      0.875"   0.695"    0.090"

Finger-hole Ergonomics
Most commercially available flutes and whistles I've seen have the finger holes all lined up in a straight row. From my point of view this is ergonomically undesirable, especially in the case of a D flute where distance between the holes makes an uncomfortable hand and finger position necessary. I find that moving the finger holes out of a straight line as indicated in the tables below allows a much more comfortable hand and finger position and easier, more convenient playing.

My wife and her sister (who both play the flute) tell me they much prefer the D-Fife described below to the D-flute because the D-Flute, even in the best of designs, has wide finger hole spacing and some large holes which are difficult to cover with small fingers.

The ergonomic offsets given do not effect the note played - feel free to experiment with alternate offsets which suit you better. Only changes in distance from the end of the flute affect the pitch of the notes.

Comparative Merits of the Designs
I've given dimensions for three different embouchure sizes and two different finger hole patterns for D flutes. The largest embouchure size, 1/2", is the loudest and takes the most wind to blow. The smaller sizes are somewhat less loud and require progressively less wind to sound a note. The smaller embouchure sizes also seem to permit more inflection of notes, allowing a note's pitch to be bent farther and easier (rolling the flute away as a note is blown generally causes the frequency to increase or "bend"). The alternate finger hole patterns given for the D flute are both manageable for a person with medium or large hands but the "A" pattern is easiest to reach. The "B" pattern is for folks with fewer drill sizes in their tool chest.

The G flute is made from the cheapest and most readily available material. The hole spacing is fine for most folks hands and it is quite loud, easy to blow and expressive.

The D Fife is quite small and also quite loud. It plays an octave higher than the D flute. My wife gets a little irritated when I run it up into the high notes where it's at it's loudest and shrillest. It seems to allow a great deal of expression in playing but takes some getting used to if you're not used to playing a small flute or piccolo. If you want something that will blast through and reach a crowded room, try it!

finally,

Flute Dimensions

( Alternate embouchure locations for G-flute: 1/2" dia.@ 15 30/32" or 13/32" dia. @ 15 15/32" . Adjust cork & blank length to place cork face 1 emb. dia. from center of hole. )

* In the tables above, where an offset "up" or "down" is given, "up" means up from the pencil line when the flute is laying on a desk in front of you with the pencil line visible and horizontal and the embouchure end of the flute on your left.

A little note: the dimensions given above were calculated using a spreadsheet from Peter Hoekje and rounded off to the nearest 1/32". I jimmied the embouchure distances on the D flute experimentally because the calculated locations didn't seem to work perfectly for me and he told me the calculated location was approximate anyway. All the designs will come in very close to the correct concert pitch if drilled as specified using the type of pipe indicated.

Peter Hoekje's spreadsheet can obtained via links on his web site or by FTP. I made some modifications (changed centimeters to inches, etc.) to his original spreadsheet and my own humble, modified version is here in Excel 4 format.  If you don't have a spreadsheet program, try this super-cool javascript-driven web page titled "Flutomat" that does the calculations.  All you need is your browser and it will let you calculate hole positions for a 6-hole flute in any key you want.

If you'd like to look at the sounds your flute makes rather than measure them you can try my own free software, Voiceprint; it's not quantitative but will give you a picture of the harmonics I mentioned.

Peter Hoekje's Musical Acoustics Page ( a teacher of musical acoustics and physics, Peter Hoekje is often quoted in web pages and on-line discussions of flute calculations and the "Benade" equations)
Rick Miller's "Simple Flutes" site (good no-nonsense PVC flute building info and valuable links)
Shambry's Pond (links to amateur flute builders, resources and other wondrous things)
What is an Irish Flute? (history, fingering chart, wonderful links to other good stuff)
The Musicians and Instrument Makers Forum (a good moderated discussion group)
Richard Robinson's Tunebook (because of course you need thousands of tunes to play)
The Pipers Corner from Chas Fowler (a musician's useful links and fine midi's)
Neanderthal Flute (for those who value truly traditional design)

And finally, some midis I couldn't resist putting up to inspire the prospective flute builder, King of the Fairies in 3 different variations: a flute solo, this more complex arrangement from which the solo was extracted, and another enchanting version. The tune in ABC notation can be found here. Clearly nothing is cast in stone and it is, after all, all about music.

Things to Come
I hope eventually to make other information available here, like discussion of the math used for calculating the hole locations and maybe a program of my own for testing flutes to be sure they play at their design pitch. What you see here is what I have finished so far after several months of on-and-off puttering. If you have questions or comments, feel free to contact me at ph_kosel@cwo.com .