How to Build the Supercorder Straight Flute

by Craig Carmichael July, August, September, October 2025.
Not Copyrighted; copy & use freely

This book now is pretty much complete.

I'm available for questions, comments, feedback.
CraigXC
at
post.
com

Chapter 1: Intro  - complete
Chapter 2: The Bore, Drills and Reamers  - complete
Chapter 3: Turning and Shaping the Outsides  - complete
Chapter 4: Tone Holes - Finger and Key Holes, Special Drilling - 'complete'
Chapter 5: Making The Keys - needs final editings
Chapter 6: Making Porcelain Beak & Block - needs final editings
Chapter 7: Tuning, Voicing, Finishing - more or less done

I created this instrument in 2003-2006. Here it is 2025. This book is long overdue.

Note: Most of the images can be viewed larger using "Open Image" in web browser.

A Few General Recorder Making Notes here

Chapter One: Intro

   I created this new musical woodwind instrument with beautiful sound from September 2003 and on through just into 2007. It started with a couple of unique design ideas. I couldn't get any recorder makers to try them and finally decided if they were ever to see the light of day I would have to make my own instrument-s. I improved on those ideas with some new ones found or occurring to me along the way. I made about twenty, of improving features. A few I sold. I have one that I still play. I've played it in music jams, and in amateur orchestras and concert bands in place of oboe or flute. (Mostly oboe - the pitch range is good and often oboe players are hard to find.) People like the sound. Fortuitously I have a very few unfinished ones and parts in various stages to use for illustrations herein, and I have held onto the various jigs and special tools, which were specially made for the job but are mostly pretty simple. I won't describe the instrument or extol its virtues here. I've done that on the general info web page and in the short videos. Fingerings are also given there.
   In order for it to "take off" and become popular, somebody needs to start making them again. I could write just enough detail and provide measurements so that experienced recorder or other woodwind instrument makers could make them. But they probably wouldn't. So instead I'm writing this complete book so that anyone who loves music and has mechanical aptitude will understand the essentials of making woodwind instruments in general and more specificly exactly how to make this new flute. There are three main areas of craftsmanship involved. I learned them as I went and I pass on my techniques herein. I'm certainly no "authority" on any of these subjects. I learned enough for what I was doing:

* Fine woodworking for the main structures of the instrument, the head and the one-piece body.
* Fine metalworking rather akin to jewelry making for the keys.
* Pottery for the porcelain mouthpiece - the unique beak and block with "as you play" fine tuning. (Of course if desired or pottery seems too hard to "get into", the mouthpiece could be done with other materials.)

   With the lovely sound and easy playing being attractive to musicians and listeners, once it is made available it's popularity will surely grow and I can see someone making a whole new and probably profitable business, even a career, out of making and supplying them. I am an inventor and was moving on into other exciting inventions even before I finished creating the final instrument - I thought about it and made a couple of ways to speed up construction - production - but really it was never about business for me.

Who wants to be first?


The Name: "Straight Flute"? "Supercorder"?

   "Supercorder" is the name I originally picked in 2003 or 2004. It reflects the origin and aspirations of the instrument. But "recorder" was always a silly (and confusing) name, only used in English. In other languages it's "block flute", "sweet flute" or "beak flute". (And I expect [could be wrong] that the name "flute" originally came from the carving of a flute into the beak of the recorder to form the windway. This would mean that the name "flute" is technicly a misnomer for transverse flute since it has no windway or flute.)
   Furthermore, many traditional "dyed in the wool" traditionalist recorder players don't even like the "supercorder", whatever the name. It's other more "mainstream" musicians who accept it as a "real instrument" and like the beautiful "recorder" tones with the strong, rich sound of the lower notes. (where most recorders are quite weak and transverse flutes sound 'thin' in the low range)
   With the reflection of time, I think "selling" it as the "Straight Flute" is probably best: descriptive and unassuming, a "natural" for everyone - especially non recorder players. It sets it apart from "transverse flute" while retaining the appropriate "flute" description. (Most people usually just call it "your flute" when talking to me, even if I had told them it was a "supercorder".)

   Officially I'll title it (unambiguously) "Supercorder Straight Flute" -- from which appellation doubtless everyone will quickly drop the word "Supercorder" to make it two syllables instead of six. I'm going to continue to call it "Supercorder" herein since that name applies to nothing else.

   Some of this info is very specific to the supercorder. Other parts may be described as pertaining to "recorders in general", "woodwinds in general", "music in general" or maybe even "Everybody knows that!

   Anyway, I hope that most musicly and mechanicly inclined readers, including those who have never thought to attempt making a woodwind instrument before, will be enabled to make a fabulous F alto straight flute by the info provided herein. ...not that the first one or the first few will be a trivial project. But potentially it could turn into a rewarding business or career.

Transposition

   Recorder has always been played with untransposed music. I learned to play F alto recorder this way. It is more flexible because it makes it natural to read parts meant for other untransposing instruments like flute, oboe, violin, piano or voice. (I suspect that if most alto recorder players go to play a really demanding piece of music on another pitch instrument, they'd have it transposed as if for F alto!) I don't care whether people adopt transposed sheet music or not, but in describing a non-transposing instrument pitched in F, we run into the confusion of nomenclature, especially for people who have always played transposed woodwinds. "All holes closed" low F on the alto recorder is described as "low C" on most wind instruments whatever the actual pitch. I am using actual pitches herein. One must therefore be aware that when I speak of Bb (for example), that note has the position and fingering that corresponds to F in transposed terms on most woodwinds. (A fourth higher or a fifth lower.)

Protect Your Hearing

A little caution: In the few years of making and endlessly tuning supercorders, I did my hearing some notable damage. With that (and everything else over the decades) I have entered "impaired" territory. Especially the higher notes, literally, can gradually be deafening. Hearing loss is cumulative and so far no one has ever found a way to make lost hearing come back.
   A good practice when practicing and playing, is to put some cotton batten in your ears. Keep a few little cotton swabs in your instrument case, and rip off a couple of pieces for your ears before you start to play. This protects them considerably without markedly muffling the sound and stifling the pleasure of playing. I wish I had known this when I was young.
   And now I've just discovered "Ohropax" wax & cotton earplugs. Somehow that's stronger hearing protection without "muffling" the sound like "headset" ear protectors, allowing one to enjoy the music. (Better for long rehearsals or sessions of tuning an instrument, which may be long the first few times until a good feel for tuning is gained.) I strongly recommend AT LEAST cotton.
   Beethoven was only the most noted of many musicians who have gone deaf. (Probably from playing a too-loud piano a lot over the years.) The last one I noted was a near deaf clarinet player who was warning people in the orchestra - and audience - to protect their hearing.
  (BTW I expect that to use a hearing aid is a "slippery slope" because once one is turning up the volume of sounds to make out speech, one is probably doing incrementally more damage, and so making sounds ever louder and more damaging.)

   Lost hearing also makes one more susceptible to 'everlasting' tinnitus, which is caused by susceptibility plus electrosmog - EMF voltage fields emanating from any oscillating electricity from 50 Hz power lines and house wiring way up to cell phones and WiFi. It often takes days to fade and no one is ever away from electricity that long, so it's 'everlasting'. Electrosmog is everywhere where people are - virtually inescapable. Along with hearing loss, perpetual ringing in the ears reduces the pleasure of music.

The Dimensions: Vibrating Air Columns and Pitches

   Obviously the length - and air volume - of a wind instrument will determine its overall pitch range. The effective length and volume of the air column determines the wavelength of the sound. One will never find a bassoon the size of a piccolo.
   Woodwind instruments play notes in a scale by opening finger or key holes that effectively shorten their length. To oversimplify, a hole half way up the tube will half its length and double the pitch - an octave higher. In general, the effective length can be increased and the pitch lowered by having a narrower tube, resisting the vibration of the air column more than a wide tube. The effective length can also be divided in half, thirds or more. One is then playing a "harmonic" of the basic pitch of that length of air column. In woodwind instruments this may be induced by having a small air hole around half way along the bore, such as the recorder's part-open thumb hole, which doubles the pitch of several otherwise identical fingerings. Double the pitch is an octave, eg, C3 instead of C2. 1.5 times pitch would be a fifth higher, eg, G2 instead of C2. So the third harmonic, splitting the air column into thirds for 3 times the pitch, would play G3 instead of C2. Fourth harmonic is C4, fifth is E4, sixth is G4, etc. Splitting the air column into multiple segments is why woodwind fingerings get "weird" going into the third octave and beyond. (Horn/brass players know the whole series to the 12th harmonic and beyond - the lip muscles select the harmonic... Am I straying far from the essential topic here?)

   The length of the supercorder is the head (142mm) + the body (377mm) + the protruding part of the beak - (minus) the length of the socket and tenon (25mm), where the two pieces overlap. Total without porcelain beak: 494mm. This length is optimized for playing down to E above middle C, up almost 3 octaves to five ledger lines C or higher. In a recorder, the actual vibrating air column is the length from the window (the hole of the whistle) down the tube to whatever holes are open to provide the different notes.
    I used wood at least 44 mm (1-3/4") square. (preferably starting out a little larger.) That leaves enough diameter for the deep labium surround in the head, and to be off a bit when drilling the long body bore.

   The supercorder body is one piece instead of the traditional two because the overlapping shafts of the key sets allow no convenient break point. Anyway it's simpler - except for having to drill quite a long straight hole for the bore. BTW in recorder or woodwind parlance the head and body are often denominated the "head joint" and the "body joint". Supercorder has no separate "foot joint".

Chapter Two: The Bore, Drills and Reamers

The the two main pieces, the Head and the Body, are each made from a block of wood. It is desirable to start with a block that is larger than the finished diameter. How much larger is desirable depends mainly on the accuracy of the drilling out of the bore. The long bore hole in the body is hardest to keep well centered in the wood by the time the drill bit comes out the far end. A reliable starting dimension is about 2 inches by 2 inches square for both pieces. So:

Head: 50mm * 50mm * 142mm (slightly longer to squared the ends off on the lathe later)
Body: 50mm * 50mm * 379mm (ditto)

With careful centering, 44 mm square is the thinnest -- unless the labium surround in the head is turned smaller than I was doing them. (I think a couple of mine were a bit smaller, eg, 42 mm. The sound may be slightly different. It might even be worth making a smaller diameter head just to hear how it affects the sound.)


   After the length of the instrument, the bore through the head and body is the most critical component. The reverse conical bore profile is part of what gives the recorder its sound character. Every minute change to the shape and volume of the bore markedly affects the tuning of the instrument. The lower octave is affected more by the length, while the upper octave (second harmonics) is affected more by the volume. So in part the two octaves are brought into tune by getting the bore and its profile right. (Not to digress... more under "Tuning".)

   The "long bore" of medieval alto recorders is the best acoustic length, while the "short bore" of baroque instruments allowed players to easily reach the low F/F# holes with their right little finger. Here keys and the longer bore are definitely a better solution. The sopranino or flautino, the tiny "piccolo" recorder an octave above the alto, seems to be always "long bore", and has more notes into the third octave than the "squashed" baroque alto, which only reaches high "G" but even lacks the F#.

   The Joachim Paetzold/Mollenhauer "Modern Alto" apparently followed the long bore of a sample medieval instrument brought to him by player Nik Tarasov, who recognized its acoustic virtues. (Whether Paetzold duplicated this bore exactly or approximately or used his own design concepts I don't know.) For Supercorder I followed the bore of the "Modern Alto". In spite of that, Supercorder turned out differently because of not undercutting the windway, which subtracted volume at the top end of the bore. This was originally accidental, but it works better!
   Later I added a semitone of length to the body to enable a solid low "E" above middle "C", and then (being out of fingers) a hole just to the side of the bell to hit "Eb" or (with a short tube in the hole) even "D". It may seem a bit hokey to play a lowest note by pressing the bell against one's leg... until one really wants that note and it's there!

Drilling the Body Bore

   After cutting the two pieces to length, the body and head bores are first drilled out and then reamed while the wood is still square. The bore hole is then used to center the wood on the lathe to turn the outside in line with the inside.
   Getting sufficiently straight hole through a long block of wood can be a challenge. I drilled the body bores with a handheld drill and three very long twist drill bits: 5/8 inch, 1/2 and 3/8. I had tape on the drill bits to mark how deep to drill, to a certain depth with 5/8 inch, deeper with 1/2 and through to the end with 3/8. The inverse conical bore is over 3/8 inch wide to the end, but a 1/2 inch hole would be wider than the reamer toward the small end. Just drilling 3/8 inch all the way would work but there'd be quite a lot of extra reaming to do. I made a drilling jig to try to get the three concentric holes straight and in line and come out the far end fairly near the center of the wood.

The body bore drills: 5/8, 1/2 and 3/8 inch by 18 inches long. Why are there four? The first 3/8 inch
bit - the one that goes all the way through - wasn't quite straight and I had to buy a second one.
(A straight one will roll smoothly on a flat surface.)




Two views of the angle iron bore drilling jig.
I had different pairs of guide blocks for slightly different cross sections of wood.
After drilling so far the drill hits the first block and one has to un-clamp
the piece and the clamp closest to it and move them closer to the front end.
By then hopefully you're off to a good straight start.

   That's just how I did it. Others might have better tools or methods. (One day I ran across a long "gun drill" bit but by then I was already doing it this way.)


Reaming the Body

   I made the body bore reamer from a piece of 1/8 x 3/4 inch mild steel bar about 450mm long. From the slight "shoulder" (image below) the shank part ends and the reaming part starts. The reaming part is long enough to go right through the body bore and do the bottom end cleanly. Two corners along the edge of the reamer are sharpened (at 90 degrees to the face) to scrape out the bore to the desired profile when one turns it clockwise. The other two edges are slightly rounded off to follow the inside curve of the bore, providing enough support that the reamer scrapes smoothly without "jitter", but not binding.


   I was usually putting the flat shank of the reamer in a vise and turning the piece of wood. Even shaving a small amount of wood at a time, a considerable force is needed to turn the reamer - easier to turn the larger square piece of wood. Later I cut down the the shank end a bit and soldered a piece of 3/8 inch pipe onto the nub, per the image. I put the reamer into a slowly turning chuck and, holding the wood (gloves!), I bored out three or four body pieces in short order. (That's prototype method (vise) versus faster "production" (chuck).)

   Many or most manufacturers have custom fluted reamers. I don't see the need myself - at least not for a few instruments. The mild steel will dull pretty quickly, and filing it will gradually alter the bore profile.

Reamers, top to bottom:
* Head Reamer (inserted to tape)
* Body Reamer (inserted t shoulder)
* Two Fine Tuning Reamers


Reamer in body piece, shown almost in to the shoulder, which is the full reaming depth.

   Here below are two sets of figures to describe the body reamer profile. The first is measured at right angles to the flat surface - the dimensions one would file or grind it to straight across before rounding off the rear edge. The second dimension is the distance between the points - the actual diameter of the bore, of the wood removed from inside. These are given as measured in millimeters with a micrometer on my actual reamer and slight discrepancies are to be expected. (Feel free to "smooth them out" (interpolate) as you see fit. [note: try these dimensions near the top: best guess for best tuning based on fine tuning reamer])
Measured at: Distance from Shoulder mm
 Width Across
mm
 Width Diagonal
mm
'0' (@2 mm)
 16.80 [17.3]
 17.16
50
 16.03 [16.1]
 16.31
100
 15.00
 15.33
150
 13.80
 13.98
200
 13.12
 13.34
250
 11.93
 12.30
300
 10.90
 11.22
350
 10.30
 10.69
380
 10.20
 10.35

   There was a second, short "fine tuning" reamer I used if necessary to raise the pitch of the "left hand" notes in the second octave. Part of it is faintly labelled "Top of Body". Farther up it says "Bottom of Head". If inserted to the line, it expanded the top of the body figures above from the "zero mm" line thus:

  0 mm 17.57 17.90
50 mm 16.40 16.79

   (Well, it's been 20 years. I can't remember how much use I made of the second, 'bottom of head/top of body' reamer, or if I reamed to the marked line or only inserted it a little bit. I do remember ten(?) years ago the instrument I play was getting out of tune. I re-reamed it with just the original body reamer and took out a few small shavings, and it was back in tune. (...to my surprise given how little material I removed.)

Drilling the Head

   I vaguely remember doing this in a drill press with a fat drill bit. After the through hole I drilled in 25mm with a drill of about 24 mm diameter to make the socket for the joint. I held the piece with a big (15 inch) crescent wrench on the square piece of wood. I also used a cheap drill press that was small enough to stall or the chuck to slip if anything jammed. It didn't have the power to yank the crescent wrench out of my hand. This was a good safety measure. Otherwise one would probably want a solid adjustable drill press vise to hold the piece. Or use a hand drill with the head piece held in a vise or with some sort of jig.  (Actually I think I started doing it that way later - same jig as the body, above. The drill press was a nuisance for it.)

Reaming the Head

   The short, fat reamer is the head reamer. Instead of 1/8 inch thickness it is 3/16 inch. The length from the lower shoulder is 126 mm. Since the bore is larger in the head, a thicker reamer will turn better, without jitter (hopefully - seemed to work). It is made similarly to the body reamer with two corners sharpened at 90° and the rear corners rounded off to follow the bore profile.

   There are really two 'shoulders' on this reamer: the lower one is at the start of the window and the reamer must be inserted no farther. The 15 mm section above this to the tape is slightly wider (~19.4 mm across, ~20 diagonal diameter on mine) and straight. It is where the beak and block go, and that thin reverse shoulder made inside the instrument prevents the block from sliding forward, which would place it below the beak and blocking the window. This position should correspond to where the upper shoulder or mark, 15 mm above, just reaches the wood of the unfinished head. The shank is whatever is above the upper mark or shoulder.

Reamed head.
Note the slight shoulder 15 mm in.

   Apparently I eventually cut a short "nub" on this reamer to insert it into a slowly turning chuck and have the machine do the work. (I don't remember doing it, but there are marks from the drill chuck on the nub.) I may, again, have held the pieces being reamed with the big crescent wrench to prevent them from turning. or not.

   My 126 mm reamer is actually more than long enough at the bottom because the 24 x 25 mm socket is cut (drilled) into the bottom area.


Measured at: Distance from Lower Shoulder
mm
 Width Across
mm
 Width Diagonal
mm
'0' (@2 mm)
 18.00
 18.52
50
 17.47
 18.16
100
 17.35
 17.83
120
 17.15
 17.75

   We'll cover cutting for the beak and block, and shaping the labium, in the chapter on the mouthpiece - the beak and block.

On my own instrument the head, top of the wood to the bottom of the delrin ring,
is just 140 mm instead of 142. I already added the ring because the wood was cut too
short and it played notably sharp unless pulled out by about the extra length of the ring.
I mention this to say the figures aren't entirely written in stone - Once you've gained some
experience, if something seems to be "off" or if you think it could be better by changing
something, realize you as the maker are always free to try adjusting or modifying it.
(PS: A ring here adds strength to help prevent the socket
from splitting, or as a repair to push it back together if split.)

Socket and Tenon

   These are 25 mm long and about 24 mm in diameter, and of course the tenon at the top of the body fits inside the socket at the bottom of the head to put the two pieces of the instrument together.
   The socket (as I recall) is drilled into the head, so its size is the drill bit size. If you have, eg, a one inch bit, that size will work. (The socket walls will be thinner unless the outside is turned a little wider.) The tenon on the body is turned on the lathe, so its diameter can be adjusted to match the socket. I'll discuss it here, although properly it's part of "turning the body", which starts the next chapter.

 The socket and tenon must fit just a bit loosely together. A strip of sheet cork is glued with contact cement to a recess turned in the tenon around 12 mm wide (see images). The greased cork seals the tenon against the socket. Air leaks will cause low notes to overblow, squeak. In order that there be no gap, generally the cork is cut a little longer than the circumference, and the ends are tapered by cutting or sanding them into opposite side "ramps" so that one end fits over the other. Cork sheets are available in different thicknesses at woodwind shops. It is sanded down until it is a good fit, generally being just slightly higher than the wood of the tenon. (Make a strip of sandpaper and half-loop it around the cork to sand it evenly.) And of course it slides in and out much more easily once it is greased with (you guessed it) cork grease from the same shop.
   Waxed thread is an alternative to cork preferred by some. Many turns of thread are wound around the thin area of the tenon. (IIRC, I think cork grease was an alternative to wax, in which case one only needs ordinary sewing thread.)

(Tip: If it's really hard to separate the instrument's pieces, repeatedly flex them back and forth very slightly in different directions while pulling rather than trying to turn them against each other if they won't budge. This may happen after a long playing session as the wood absorbs moisture and the tenon swells more than the socket.)

Two tenons, the top one without cork.
The socket should be square - ~24 mm I.D. along its length and 25 mm long, to match the tenon.
-- Also of Note --
These were an 'early' and 'latest' design. Body length increased with the
addition of low E, and my built-in "thumb rest" changed to a gentle "thumb guide".
Some scoff at thumb rests, but with the fine tuning done by moving the instrument
slightly toward and away from the lip, something to push "up" on with the thumb is helpful. The
right thumb is the only free digit, which also holds up the instrument regardless of fingerings.


Chapter 3: Turning and Shaping the Outsides

   After making the bores, those end holes are used to center the piece of wood on a lathe so that the outside exactly lines up with the bore. (I'm not going to talk about how to use a wood lathe and turning tools. I turned a wooden bowl in school when I was about 15. I'm sure there's lots of info and videos on line.) A 45° "live center" on the tail stock should hold the lower end of the body. No doubt one will need to make pieces to fit and center the bore holes and the socket on the head to the lathe drive. I don't remember what I used. (Hmm... There are some pieces in the box that look like that was their purpose.)

   One should look at the photos to see the outside profile. I wasn't very careful about duplicating exact outer diameters as I turned new instruments, especially on the head and the upper section of the body. This (in retrospect: of course!) led to the finger holes needing to be slightly different sizes since they went through different thicknesses of wood, making different "chimney heights" per woodwind terminology. Luckily this can be adjusted by (typicly) reaming the tone holes from the inside to expand them and raise the pitch. (see chapter on "tuning") If the body is too thin, it my be hard to anchor the posts that hold the keys. (The thinnest wall sections are probably at both posts of the Eb-Db ring keys, especially the top post.)
   The top of the body diameter (excluding tenon) should match the bottom of the head, on my instruments about 32 mm. thicker wood around the socket reduces the chance of it splitting. The built-in right hand 'thumb rest' or 'thumb guide' rises to about 32-36 mm. The 'left hand' section between is a shallow concave. (The lower instrument above is larger: 34 at top of body and 36 at the thumb guide.
The head hits 47.5 mm at the widest area. If I was ever to complete this instrument I might want to turn it down further.)
   I started aiming for about 24 mm O.D. on the straight lower 'right hand' section. (Hmm, the micrometer says 23.6 is typical.) Since this is the narrow end of the inverse conical bore this smaller diameter still leaves good wall thickness.
   One might make a template to consistently turn to the desired contours and diameter.

   One will note in the image above (at end of previous chapter) that I left a built-in "thumb rest" or "thumb guide" where the right thumb supports the instrument while playing. I thought it was a cool idea, and with moving the instrument toward and away from the lip for fine tuning, it has more value than expected on a small instrument. It has a secondary purpose of making a thicker area to mount the B-Bb pipe-key. Later I changed the "thumb rest" to a more gentle "thumb guide" as shown. (If you don't like the idea of building in a thumb rest or guide at all... it's not vital. You're the one on the lathe!)

   The flare on the outside of the bell, except as it might very slightly affect tuning of low E (and Eb, D), is pretty much decorative. (I suppose it's also more blunt if one got poked by the end of the instrument.) I didn't notice a difference by flaring it on the inside. (Theoreticly maybe low E is a bit louder? ...and sharper?, but one would tune after shaping the body.)
   The diameter for the extra low Eb tone hole will be affected by bell changes.

- - - -

The head as I made them is quite large in diameter at the top end, around 44 mm (42-44) at or just below the window, so the windway is cut in very deep. I heard "shading" the windway made the low notes better and decided to make it that way. I think it's what gives it the somewhat "clarinetish", richer low notes. The head then tapers down to the top-of-body diameter, again about 32 mm. I didn't experiment much with this layout. Trying out different widths and profiles (labium depths and surrounds) once you've got a bit of experience wouldn't be amiss.



Sometimes I made a delrin ring between the head and the body.
I turned them inside and out on the lathe from a solid delrin cylinder.
The bottom of the head has to be turned down so the ring fits over.
Aside from appearance, one can be added if the head wood is starting to split at the socket,
...or to add a little length to a "bit too short" instrument for best tuning.

Mounting for Mouthpiece

   The porcelain mouthpiece, beak and block, is mounted on the wood at the top of the head. Owing to it being a separate piece, the voicing is adjusted in part by setting the height and aim of the windway in the mouthpiece, which I did with shims.
   I confess to thinking the way I did them may not be the most elegant possible solution. But it works. The "rib" I put on my beaks, forming a groove for the retainer, is obviously unnecessary since they can't slide forward. Other than the obvious step of eliminating that rib in any new fabrications, one is welcome to try to dream up some better design.
Head - Mouthpiece Disassembled - 3 views





   The cut-out is an "L", 15mm in from the top end of the head going down to 1/2 way through it. Then cutting in 15mm from the end to meet that. Again this cut-out should be made so edge grain is at the top for the labium.
   Two holes are made through the flats for the retainer, half way 7.5mm from the end and from the bottom of the cut. They should be about 32mm apart, or 16mm each side of center. (All to the centers of the holes.) I then drilled a wider diameter flat area from the bottoms, so the nuts of the retainer screw into a flat area. IIRC for this I ground the end of a drill bit flat instead of angled, ad held everything solid in a drill press.


Labium: Window, Edge, Ramp

   This is a wood carving exercise involving a fine saw, hammer and chisel, and finer tools including (say) "xacto" knife, a small file and a very small sanding block on a stick. It is best shown in the fotos.





   Defining the "top" as the front of the window touched by the mouthpiece and the "bottom" as where the ramp (smoothly or abruptly - style choice) meets the outside of the head, roughly the dimensions are:

Ramp + window, top to bottom: 52mm (without window 48mm. Bottom foto) I have one (top foto - needs sanding) that curves and tapers to meet the outside gradually that's 75mm long, so obviously great variation is possible. Shorter probably looks nicer. I doubt that it affects the sound appreciably.
Window: 4mm long, about 16mm wide (measured straight across).
Ramp width:
- Top at outside of body: around 20mm (measured straight across)
- Bottom: 21-25mm

   My first step is to cut the sides of the labium with a fine saw. One starts from no depth at the bottom, deeper and deeper toward the top. Since it involves estimation of the depth and exact positions of the cuts (unless one makes some jig for production), it's probably best to cut less and deepen it later than to cut too deep and have edges of the ramp with grooves in them - or worse, to cut into the critical window edge area.
   Then I start hacking with hammer and chisel, again stopping this crude process before going too deep and changing to scraping, files and sandpaper. Make the window edge thin and sharp and 4mm long as a final step.

   A key point is that the cleaner and sharper the edge below the window, the clearer and sharper the sound. "Sharp" suggests not having the ramp rise up thickly to the body too soon, especially if it's a convex curve "taper" top to bottom. Likewise, a 4mm window length seems to make the best sound. Great care is needed to form the window and its immediate surrounds. The sides of the ramp should match the sides of the windway in the mouthpiece as well as possible.

Chapter 4: Tone Holes - Finger and Key Holes

   Of course the finger holes go on top and the thumb hole on the bottom. Key holes are rotated as convenient for the mechanism WRT convenient finger positions. In general woodwind practice, the top and bottom are the edge grain of the wood, with the flat grain at the sides. The same applies to the head: the labium is at the top and the grain is oriented up-down.

   The supercorder generally follows recorder fingerings for notes in its natural key, F, but there are exceptions. (See the fingerings chart.) Sharps and flats are made stronger and generally easier by means of several keys, which allow an optimally placed hole for every semitone. I managed to make this instrument "fully keyed" with just seven keys, which includes a low E key for an "extra" (and often useful) note below low F. Additionally, every key pressed closes a hole and lowers the pitch, where on other wind instruments pressing certain keys opens a hole and raises the pitch. Closing and lowering makes for more intuitive fingerings.
   In addition, lateral finger movement to another key is never necessary. One is either pressing or not pressing a finger down, with some variance for B/Bb (right index finger touch or press) and the little fingers double keys (two positions or curl finger).

   I am going to boldly claim that supercorder is easier to play in any key than any other chromatic woodwind instrument. I've played often in A and E and even B (music jams, songs) as well as Bb, Eb and Ab (concert band music is usually in flat keys). Etc. By contrast, for example Bb clarinet has all the chromatic notes, but a player may balk if asked to play "allegro" in keys with more than one or two sharps (which is three or four sharps on that clarinet) - Instead they make separate "A" clarinets for playing in sharp keys. It seems to me that would be essentially superfluous for supercorder.

   In hole placement, tuning of the lower octave is most affected by the position of the hole - its distance from the window. Tuning of the second octave however is somewhat more affected by the size of the hole than its position. Therefore, to get both octaves in tune, each hole must be in the right place and the right size. And the right place and size are very dependent on the bore. Since supercorder's bore is unique, so are the hole placements. Starting from the "modern alto" recorder I did much experimenting to determine the best places for the supercorder holes, as a look at the experimental hole jig below will show. I moved the holes around, and changed their size, by soldering and unsoldering washers or pennies with holes in them, replacing them if the hole was too large. and then making another instrument. From the first marginally satisfactory instruments they were honed to something approaching perfection.

The experimental tone hole placement jig


Underside view



Final hole drilling jig.
(Don't worry - table of exact hole positions & sizes is below)


From underneath


(Position of each hole is given below)


Two more views.
(Remember use "open image" to enlarge.)

Discussion of the tone holes and keys

   Starting from the top, one notices (in some other foto or in the jigs, above) that the thumb hole is a little higher up than on most recorders. It seemed to be the best placement. It allows second octave Bb and B (as well as G# and A) to be played with the thumb open and it surely improves second octave D, Eb and E. (hmm... "2nd octave" NOT counting the "extra" low notes below low F!) I also moved the F#/E tone hole (1st finger) up a little for E to be in tune in the second octave. (E can be played as  / XOO OOOO IF all is in alignment. E can also played reliably as / XOOXXXO even if the voicing is slightly out. Obviously the first is the easier to play in a run of notes.)
   Second octave Eb and E are the most critical notes for voicing. E played as / XOO OOOO requires precise windway alignment. (I have a whole collection of blocks and beaks. One must select a pair that work together well, and get just the right amount of shims under the block. On my instrument I find it works best if the block is pushed out maybe 1/2 a millimeter compared to the beak. (On other recorders 2nd octave E as / XOO OOOO will not sound at all. But more on those items in the "voicing" chapter.)

   Back to the lower octave, left hand notes... Many have noted that F# as X OOO OOOO is a bit flat if all the other notes are in tune, and that there is no viable fingering where it's in tune. Apparently this is inherent, but on supercorder O XOO OXOO makes an well-tuned F#, so I consider that to be the normal fingering. (Thumb-only F# is still good for some trills & runs.)


   At some point I conceived that as E and D were in up the left hand, Eb and Db could most easily be played by using ("adding") the middle fingers of the right hand, which are not otherwise in use in this pitch range and which only closed a simple hole, no keys. Closing either of these two right hand holes alone had almost no effect on the notes in this range. Thus for these notes I conceived the pair of keys linked to right finger rings, allowing an optimum tone hole for every semitone C-Db-D-Eb-E, as was already achieved for the rest of the scale. It worked marvelously! And again, pressing a finger down lowers the pitch as is intuitive, never raises it. (This idea expanded on a clarinet Bb fingering - what luck that someone had just given me a clarinet ["fix it yourself"], as I'd never have bought or closely examined one otherwise!)
   So, E is played as expected, T XOO OOOO, and Eb is T XOO OXOO. Similarly for D and Db: T XXO OOOO and T XXO OOXO. In runs with Eb the right middle finger can simply be held down, eg, held down for the whole sequence: C D Eb F G. (None of the other notes are made flatter by this because 2nd left is held down for all them except E (Eb) itself. Unfortunately this doesn't apply to the Db.)
   I originally conceived that Eb and Db could also be played by moving the finger (L2, L3) up a bit and pressing the 'flat' key with the left hand without covering the hole. This works fine but I haven't found it to be practical or useful for playing  music. Using the right finger is easier.

My first renditions of this idea weren't very good or practical. I finally made them with rings much more like the clarinet's. (I had mercifully managed to forget the first version ever existed until I was digging through boxes and instrument cases for this book.)


First try at Eb & Db keys.
The ring keys way is much better


    The C-B-Bb telescoping pipe is unique. It was one of my original inspirations for starting the project. Needing to play both these notes is a headache on wind instruments, usually involving a "forked" fingering for one or the other or both. My solution to play either note with only the right index finger was to lightly cover a hole to get B, and to push a bit harder to depress the Bb key as well, for Bb and all lower notes. It works quite well.
   While it simplifies playing it does have two disadvantages: first, it increases the distance between the first and second right hand fingers, a tone hole being between them. It's doubtless fine for most adults at the F-alto size, but it probably wouldn't scale well to a longer, lower pitched instrument. The second is that it's harder to make a smoothly working, air leak free telescoping tube than the other keys.

   The second and third right fingers cover their own tone hole as is typical (note below). In addition, they press down the rings linking to the Eb and the Db key. When playing notes in the right hand fingering areas, those rings are pressed down already by the left fingers. In the left hand fingering areas, the otherwise idle right hand is employed to make playing the above mentioned "non C scale" notes simple.

   It is traditional to offset the hole for the third left finger a bit to make it easier to reach, but not the third right finger. I offset mine a bit for a special reason: I'm missing the last joint of that finger [skillsaw accident when young] and I have to be able to play the instruments I make. Every little bit less I have to reach helps. But many players hold wind instruments, especially keyless recorders, pointed a bit to the right. This offset for the third finger, with the further offset to the F/F# keys on the fourth finger, might improve the ergonomics back to "straight"? I myself can't have a proper feel for this. (If I was missing just a bit more, woodwind playing would be "out" for me and I'd never have developed this instrument!) You as the maker may choose to offset this hole or not, which is typicly (maybe just "traditionally"?) made in-line. It makes sense to have it in-line if the fourth finger has to reach over to an un-keyed double tone hole. That's not the case here.

   On recorders the third finger usually covers a double tone hole for A-G#-G. But this arrangement makes low G# and A weak, and G# harder to play (especially along with transitions between G# and any lower notes), so we opt for a separate accousticly optimum G#-G tone hole, which is played by the fourth finger of the left hand via a key. The right third finger covers the A-G# tone hole. This seems perhaps unintuitive, but transverse flute in fact does the same thing with the same finger, except that the key is held down to Open the G#-G (D#-D in transposed terms) hole instead of to Close it. It is thus held down for all notes above G (D). On supercorder it is only held down for the very few lowest few notes in the lowest octave: G, F#, F and E. And since "second octave" G is usually played with a "lower octave" note fingering (O OXO OOOO), having / XXX XXXO play G# instead of G actually makes for easier fingerings in mid ranges.
   (Also it can also make for smoother trills, G-A as O XXXx XXtO or G-G# as O XXXt XXXO, or better tuned with part thumb. or even: X OXXx XXtO, X OXXt XXXO. Options, options!)

   I considered instead making an A-G#-G pipe-key similar to the C-B-Bb pipe-key. But I rather doubt that it would be practical. The pipe-key is easy to just touch to get B with the sensitive index finger because the right hand fingers are otherwise free just at that note. But with the first two fingers held down, the third finger is probably much less free and nimble to touch and play G#. Anyway because I am missing the whole last joint of that finger myself, I would have great difficulty to operate such a key freely. I couldn't try it out and evaluate its efficacy for other users. (I would apply that same argument to Eb and Db on the left hand.)

   The low G-F# and F#-F tone holes and keys are essentially copied from the "Modern Alto" recorder. (It is unfortunate on that instrument to go from a nice, strong low F, F# and G to substantially weaker notes G# and A (not to mention Bb and B above that.)

   With no more fingers being available I put one last narrow tone hole down right by the bell. If all holes and keys are closed with the fingers and the bell is covered by the leg, A low Eb (E-flat) below low E results. Or, by inserting the "low D pipe" in that hole, it is lowered even more to low D. Unfortunately D and Eb aren't both available except by inserting or removing the short tube. Anyway they are weaker notes and slow to sound. (Even the low E is slow to speak. But after all, most alto recorders only play down to F and notes under about C above that are all weak.)

  F alto doesn't go quite as low as some common C instruments, so every extra low note helps when one is playing music not specificly written for the instrument. Old flutes and Celtic music often go down to D, and for example in Bach's A minor violin concerto it's surprising how seldom one must go up an octave or play a "harmony" note if low Eb is available in the first movement, and low D in the second. An A-minor recorder concerto by Vivaldi (RV445) goes down to E in multiple runs and can't be played as written on most recorders. This is why I pushed the limits with the low E key, and then low Eb or D by "trickery".

   Low E is surely the lowest note that a composer should write in creating parts specificly for this instrument, but even in the lowest range there are no particular constraints on note sequences. It's pretty easy to play any note from E up after any other note.
   At the top end, notes above 5 ledger lines C on supercorder are mostly highly questionable (except that high-high F is piercing). Anything below that C is fair game (if the player is wearing ear protection). Luckily not much music is written way up there anyway... unless it's piccolo or soprano/sopranino recorder playing 8va. (also ear protection!)

=====

   The table below gives the distance to the center and the size of each tone hole from the top of the body without counting the tenon. These are as measured or marked on my hole drilling jig, and were derived from considerable experimentation. Apologies for the mix of units. Being in North America, all my drill bits were in 64ths of an inch. (Inches would be fine to use too if tool and bolt sizes were decimals of an inch instead of "64ths". Instead one measures (eg) ".567" on the micrometer and then must convert that to n/64ths. Also ...15/64, 1/4, 17/64, 9/32... is confusing.)

   In sizing the hole drills, it was intended that the holes never be drilled too large, which would make notes too sharp. Rather, they may be a bit undersize (note flat) so that removing a bit of surrounding wood will raise the pitch until it's in tune. Then they can be reamed out bit by bit from inside with a 'dremmel moto tool' burr bit. The burr bits I used were small, shaped round and inverse cone. The small burrs fit though the hole and so are able to ream it from the inside face so that the outside face of the hole is unchanged.
   More traditionally bits of wood are scraped from around the hole with a small knife. The dremmel burrs are much faster - also easy to go too far.


   Holes that are too large (note is sharp) can be reduced using cyanoacrylate glue mixed with sawdust from the recorder's own wood (save a little!) to reduce one side of the hole. (Other glues I tried tended to eventually dissolve or come loose with the moisture of playing.)


Finger (Notes when hole is the top open hole, closed) [Rotation from in-line with other fingers - degrees]
 Distance in mm
 Hole size in inches
Left Hand

Thumb (G, F#) [180] 18.5
 1/4
1 (F#, E)
 44.5
 1/4
(E, Eb)
 68
 3/16
2 (Eb, D)
 82
 3/16
(D, C#)
 97.5
 3/16
3 (C#, C) [left ~ 4 mm but usually drilled straight down]
 114
 3/16
Right Hand (mostly!)

"4" - index finger (C, B)
(B, Bb pipe)
 131.5
 11/32
(B, Bb)
(B, Bb pipe)		 152
 3/16
"5" (Bb, A)
 173.5
 3/16
"6" (A, G#) [may be in-line or ~4 mm right (see text), but drilled straight down]
 196.5
 13/64
"8" (G#, G) [0° - in line]
(LEFT little finger, double key)
 220.5
 7/32
"7" (G, F#) [75°(?) right]
(RIGHT little finger, bottom lever double key)
 255
 5/16*
(?jig says
11/32?)
(F#, F) [75°(?) right]
(RIGHT little finger, top lever double key)
 280
 5/16*
"8" (F, E) [0]
(LEFT little finger, double key)
 310.5
 11/32
(Try 5/16*,
undercut?
BELL STOPPED (E, Eb, or E, D with "D" tube)
 347
 1/4
*Without having done it myself, I suggest making these three holes the same size
(undercutting if/as necessary to tune) so they can all use the same key pad & pad cap size.

   In addition to the toneholes, there are six threaded holes to hold the "posts" (AKA "pedestals") for the rods on which the three sets of double keys pivot. These holes are all the same size depending on the diameter and threads of the pedestals.
   I got some pedestals off scrapped clarinets, others I made myself. Some of the clarinet ones have very coarse threads. IIRC these were for plastic clarinets. Generally makers are careful that the holes for their pedestal anchors stop short of penetrating into the bore. So ideally to thread the holes one needs a "blind" or "bottoming" threading tap, ie, one that will thread pretty much right to the bottom of a hole since it ends without going right through the wood. (I suppose it wouldn't hurt much if the holes protrude into the interior - the tiny space they would add could hardly affect the tuning. But if the bottom of a metal pedestal anchor sticks in to the bore, it will either stop or damage the bore reamer. ...and after drilling through into the bore, one will want to run the reamer through it again. Also after some years of playing, an instrument often wants the bore reamer run through it again to shave off roughening wood inside, that can affect sound quality and tuning.)
Pillar Key Set
 Distance Down (top hole, mm)
 Distance Down (bottom hole, mm)
 Angle from in-line with finger holes (degrees)
Eb - Db
 63
 158.5
 90° to right
G - E
 135.5
 318
 90° to left
F# - F
 231
 287
 25° (?) to right

   These angles need not be set in stone - perhaps some are not optimum. But they work. I chose them as practical and "operable" while keeping them out of the way of other keys and the fingers. To start with I tried to make the F and F# keys the same as the "Modern Alto" recorder. The G/E key mechanism then had to work around those, and then the Eb-Db then had to work around the B/Bb pipe-key and the G/E.
   The diameter of the post holes depends on the post's anchor diameter and threads. On my own instrument it looks like I used pillars of a scrapped clarinet. They're about 4 mm in diameter. I don't remember about the threads (and at the moment I decline to disassemble the keys including the pillars).
   For those pillars I made myself, I probably used #6 AWG solid nickel-brass or brass wire or rod cut into short pieces, and threaded them with #10-24 threads, which would mean a drill bit of about 9/64 inches and a #10-24 "bottoming" or "blind hole" tap to drill the holes and cut the threads into the wood. (More in the "Making The Keys" chapter.)

   Tone holes with keys have a special surround. The key pad has to seal against a flat surface, in contrast to the fingers which can cover over the slight curve of the round body. The surround is a slight depression drilled in with a special drill. (Look at a clarinet or an oboe.) I made my pad surround drills by shaping flat "spade" drill bits to the shape I wanted with a file, and soldering a little piece of round brass pipe to the center. The pipe keeps the bit centered on the hole without drilling out any more on the sides of the tone hole.

Tone holes with a ring around them have a different special surround - a little "ditch" just outside of the immediately surrounding wood. The requirement here is that the finger be able to close the hole normally, which means being able to press the ring down until the top of the metal is roughly flush with the surface of the body. Again a special drill bit is shaped as desired.

Specially Shaped Drill Bits  (L to R)
* The bit with the large center nub is to shape the surround of the low E keyed hole. (It's about 16 mm.)
* The similar bit marked (14) mm with the smaller brass tube center is for the Bb and low G, F# anf F keyed holes.
* The third bit marked (8) mm is for the left hand keyed holes Eb and Db. The center is dulled so it won't cut into the tone holes.
* The "notched" bit is for the surrounds of the holes with rings around them: left hand E, D and right hand A, G#.
* Gratuitously included in the drawing: tapered spade bits can make it easier to drill large holes in wood. The tapered edges are sharpened like the flat ends.

   All the hole-surround drilling is best done on a drill press with the instrument body clamped down so it can't tilt or shift. I made a holder jig for holding the body steady for such work, with the tenon fitting into a socket on the jig.

   In drilling a couple of new surrounds for the images below with the above 14 mm bit, I didn't use the center-surround at all. I just tried to center the bit as the surround was too small for the holes.
   I used 10 mm pads for the G key, 12 mm for F# & F keys, and 14 mm for the E key. One might get away with drilling the low E tone hole the same size as F# & F, and using a 12 mm pad, to reduce the number of sizes, and undercutting to tune it sharper if F is flat. (or move the hole a touch closer to the labium?) One could use the same size for the G as well - it would just be larger than needed for that hole.

Body Holding Jig.


"Demo": drilling a keyed tone hole surround.
I clamped everything solidly on the drill press, positioned
carefully, and didn't use the center of the drill bit at all.
It seems to me that at least sometimes I carefully filed off roughness
afterward to make the center area more flat and smooth. (This may have
been for coarse grained wood such as the purpleheart shown.
or a dull bit? or poor drill alignment?)

Chapter 5: Making The Keys

(What? There's more to it?!?)

   When I've shown people my flute I've been asked many times "Where did you get the keys?" Well, wouldn't that have been convenient, to have just "got" the keys!

   Metalworking for the keys is more like jewelry making than typical metal work. But different again. There are specific components to the keys, which in supercorder is three sets of double keys. That's six pivoting keys with just three similar sets of posts and axles. (The remaining C-B-Bb tube-key is discussed separately, farther down.)

   The metals commonly used for keywork are brass (eg, Cu:Zn 83:17%), or "nickel-silver" (AKA "German-silver", or as I would prefer to call it, "nickel-brass"). (eg, Cu:Zn:Ni, eg 65:17:18%) It is 'silver' colored but has no silver (Ag) in it. These are also the metals commonly used to make 'yellow' and 'silver' brass instruments. Yellow brass tarnishes and so is generally laquered. Nickel-silver generally stays shiny. I tried gold electroplating of keys but the process I tried didn't work very well for me. Then I tried "Liquid Tin" from an electronics supply store ("MG Chemicals" IIRC). Dipping brass in that turned it silvery quite well but it's likely to wear off of the finger rests. I came to much prefer the silver colored "stays shiny" nickel-silver, which is also the color of the solder.
   Both metals are ductile and malleable, so they can be formed and worked to different shapes. The silvery one with nickel is somewhat harder. I bought brass tubes for keys from a hobby shop, "K & S Brass". I had to form my own nickel-silver tubes from sheet metal. (with a "wire drawing plate", discussed somewhere below.)

Brass rod & similar diameter #6 AWG nickel-silver solid bare wire, plus a #28 N-S sheet.
The wire, sold in a coil, is obviously annealed to roll up. Straight rods are more likely hardened.
The bottom N-S piece has been flattened to make a key. (so it has become at least partially hardened.)

   (Actual silver is too soft. Keys would bend. Straight copper would be too soft, too... otherwise it might be an interesting key color. Bronze? Then again, 'silver' matches the solder.)


   In typical woodwind keys the pivoting parts of the key - the finger rest, the joiner arm from that to the axle tube, the axle tube, the joiner arm from the axle tube to the pad cap, the pad cap itself and the spring rest - are all separate pieces of metal, silver soldered together. I made my first keys this way. (Except I used soft solder. It held up fine for the one summer playing season I used it.) BTW IIRC what I'm calling "pad caps" are more commonly called "pad cups".

My Early Version Keys - "typical" woodwind key forms.
(The open tube on the third right finger hole was just for me. It helped my missing
finger tip reach the hole, with a more natural hand position for pressing F# & F.
This became impractical when I added the Eb & Db ring-keys...
I never intended this new instrument to be just for me!)

Novel Keys Design

"Brackets" for low F# & F keys, nickel-silver & brass
   But after that I started forming the moving part of the keys out of just four pieces - the axle tube, the pad cap, the spring rest, and a single "bracket" piece something like a "U" (or "[") with a finger rest tail, bent around in three dimensions to form the finger rest and the rest of the parts between and holding the pad cap. This takes all the twisting strains. With this arrangement the tubes have no tendency to twist, and the two or three soldered joins take very little strain. So I just used soft solder - the "modern" "silver bearing solder" (tin alloy) often used in electronics. (Eg, Sn:Cu:Ag 93.6:4.7:1.7%), with resin core. Not to be confused with much harder, high temperature "silver solder", made of various mainly silver (Ag) alloys.) I did try to make a large common surface area of solder join and to get more solder built up around the edges, especially for the ring keys, whose finger pieces do take some strain.
   The little bits for that the springs work against are also soft soldered, and again I have never had one come loose.


   In 19 years, at least with my own instrument, I have never had any trouble from this arrangement or from the soft solder joins, including with the ring keys. Because of not heating the pieces to red hot to silver solder them, they stay shiny and don't need cleaning up and re-shining. The solder is likewise bright silvery color. The bracket piece is "work hardened" by flattening and bending it, instead of becoming annealed by heating it red hot, so it is strong and durable. Technicly, the tube isn't required at all except as a spacer on double keys. The bracket can just pivot directly on the steel axle rod with a pivot hole near the base of each arm. As spacers, the tubes really don't even have to be soldered, just slid onto the shaft. (For a thin spacer, a tiny washer should be fine. I didn't bother to use any myself.)
   The six 'regular' keys are all double keys. Two of the three pairs are an 'inner' and 'outer' key. The two ring keys however must overlap, which is done at the lower ends. If the posts are just before and behind the arms, the outer key needs no tube. This is also strongest because the holes in the arm are small - the diameter of the axle rather than of the tube. For the inner key, a soldered tube would best run the full length between the two arms of the bracket of the outer key. The inner key could be soldered to the tube to keep it from sliding up and down the axle shaft, or could also have small holes just for the axle and the tube (and washers?) would be slid on as spacers.
   I sometimes used small holes and unsoldered spacers, especially on later instruments, but more often soldered tubes to the brackets. I didn't use any washers. (If the key works fine are washers superfluous?) I can't say I was consistent - my mind was at first stuck on the idea that keys should be soldered to tubes as they must be with "regular" key making. But the variations were evolving. Now I think unsoldered spacer tubes might be best, with the smaller 'axle size' pivot holes in the bracket arms being stronger.


1. "pillars" or "posts" (Brass or Nickel-Silver... B or N-S).
2. axle (piano wire 2.36 mm [as measured])
3. axle tubes (B or N-S)
4. Brackets (B or N-S) The one piece finger rest plus pivoting linkage to hold the pad cap.
5. pad caps (B or N-S) These hold the pads that cover the holes.
6. rests (B or N-S)
7. springs (piano wire .64 mm [as measured])
8. Pads (I used five or four 'clarinet' type pads and two or three thin 'oboe' pads)


Pillars (AKA Posts)

   The pillars consist of a threaded bottom section that is screwed into the body of the instrument to hold it in place, an upper cross hole near the top (~5 mm up from the body) to hold the axle rod, and another tiny cross hole about 4 mm underneath that to hold the spring. IIRC I used a 'dremmel' type tool to drill the holes.
   The easy way is to leave the piece of rod whole and thread the end, then drill the holes. First I flattened the spot on the post or center punched it so the drill wouldn't veer off. Once it's done, cut it off above the top hole to separate the short post from the rod. The top can then be rounded off and any other desired shaping can be done. (Perhaps make a thicker rod, threaded inside in the center, to screw it into, so it can be mounted in the lathe or drill press chuck? Wait! Just use a #10-24 nut! A coupling nut would be good if those are made in 10-24.)

Threading base of post. Rod is held in vise with rag to prevent marking,
#10-24 threading die. Thread length is about 5 mm (3/16"),
which is then also the depth of the threads in the holes in the body.

Various posts (pillars), some taken from clarinets,
some I made of brass or nickel-silver, some with key springs.
I did a bit of trying out different shapes.
(Isn't the wider #10-24 going to hold better than those narrow clarinet 'roots'?)
(IIRC the ones with very coarse threads were for plastic clarinets.)

   The spring is a fine, straight piece of piano wire extending under the key mechanism. Mine measured 0.64 mm diameter. They vary slightly in length depending on the key, around 20-30 mm. I found piano wire at a hobby shop in 3 foot lengths. (not long enough for a piano!) The hobby shop was also the source for the tiny drill bits needed for such work. If the spring is slightly loose, slightly bending the end segment that will be inside the post should tighten it in place once it's pushed in (with small pliers). OTOH if it's tight, twisting the spring as you push may help get it in.
   For each pair of posts, one axle hole is drilled out the diameter to slip the axle rod through, and the other end is drilled smaller to be threaded to hold it in place once inserted. As I measure my instrument the axle cross holes in the pillars are all centered about 5.5 mm out from the body except the lower one for the ring keys, which is 7.5 mm. (The body is thinner at that end of the axle than at the top end.)
   Since the axle rod has to be inserted from one end... the easy end is the top for the ring keys and the G/E keys, and the lower end for the F/F# keys. The threaded post should be the one at the other end.

Axle Rods

   The axle rods are of hard piano wire. ("Spring Steel", is it?) The ones I used measured about 2.36 mm diameter according to my micrometer calipers. They each go between two posts. They are the pivot around which the keys rotate when pressed. One end must be threaded to match its post. The other end needs a slot cut into it with a very fine saw (hobby shop) so the axle can be turned in and tightened with a tiny slot screwdriver. The threads and slot are hard cutting in the hard steel. I must have used the finest saw to cut the slots. I threaded one post and the rod end with #4-40 threads. (metric: try 2.5 mm O.D. threads?)

Threading an axle. I just clamp the rod in a vise and turn the #4-40 die,
which is to match the #4-40 inside thread in the hole in the post.
(Um, ignore my clutter!)


I used this very thin saw with very fine teeth from a hobby shop to cut the screwdriver
slot in the end of the axle, also to cut brass or nickel-brass tubes & rods.


The length for the axles are:

Ring keys - 99 mm (unless extended)
F/F# keys - 60 mm
G/E keys - 188 mm

   Axles are generally cut the exact length between the outsides of the posts but nothing is lost if one end sticks out a bit. Leaving an extra mm or two will allow in case the threads are a bit long, where the threaded end will stick out past the post before it's a tight fit. (One can grind off the excess later if desired and if necessary extend the threads, but it would be a nuisance to grind off the screwdriver slot and have to cut another one.)

Brackets

   These are the one-piece "main" pivoting piece of the key. They are made of solid #6 AWG wire or rod, nickel-silver or brass. The G-E key and F#-F key for the left and right fourth fingers are bent into four sections:

1) pad cap arm
2) connector length
3) finger rest arm
4) finger rest

   The first three sections are flattened verticly, that is, made to be a tall, flat sided oval. The finger rest is flattened horizontally instead, at approximately a right angle to the rest. The arm holding the pad cap is curved around the body of the instrument.

F & F# key brackets


G & E Key brackets.
The top ones are brass, some dipped in "Liquid Tin" from an electronics store.
The lower pair is nickel-silver.
Some of them have pad caps and pads.
Note the single full length spacer tube on G key of the bottom set.
With the top pair, a spacer tube simply slipped on the axle on the
lower section would prevent the G key from sliding down the axle.


Another view.

   For the rings key's brackets, Eb and Db, the "finger rest" section is replaced by bends to connect the rings around the right middle finger holes, and they are the same oval profile as the rest of the bracket. The rings and the pad caps are special shapes. I think I used a flat ended punch to indent the key from underneath to form the pad cap. I probably punched that into a nut with smoothed inner edges, but I don't remember. I used thin 8 mm oboe pads in the small depressions made.

The Eb & Db ring keys:
posts with springs on body,
axle (on table) threaded at the bottom end & screwdriver slot at the top.
The plastic screw in the body stops these keys from opening too wide.
(The screw was easily adjustable.
Cork or ??? glued to the body is fine too.)


With axle rod screwed onto posts.


(assembled)

  There are two ways to flatten the rod. The first way is with a smooth-faced hammer and anvil, gradually flattening by pounding along the length. (If your hammer is all gouged up from pounding nails, you may want to grind and or file it smooth.) The second way is to use a jewelers rolling mill. This is quieter, smoother and somewhat faster but certainly not vital for one or a few instruments.
   Both methods will increase the length of the piece, so with practice one may cut the rod a bit shorter than the desired length. (A little different than cutting wood, eh?) Pounding will increase the length and the height of the oval cross section; the rolling mill will stretch the length more than the height.
   This also provides a means to adjust the length of the bracket for a good fit even after the arms have been bent.

   I don't remember the exact length of the brackets, but clues may be taken from the metal jig for the length between the insides of the arms:

Eb: ?
Db: ?
G:   75 mm
F#: 17
F:   45
Low E: 171

And also for Eb, F and Low E, one might use the distance between posts on the body (subtract one post width).

Or, measuring my own instrument, I get (to the middles of the arms):

Eb: 88 mm
Db: 56
G:   79
F#: 18
F:    45
Low E: 175

This may be the most practical since it is actual measurements.


   I don't remember whether I drilled the axle holes before or after I bent the brackets. At least center punch the two points first. If they are drilled before, care must be taken not to stress the area of the hole when bending, or it may bend there instead of at the desired point. Smaller axle size holes will weaken the spot less than larger ones sized for the outer tube. Drilling after may be difficult, and will probably have to be done with a portable drill or dremmel, rather than a drill press.

   Depending on the metal it may be necessary to anneal it before working it, or it may break at the sharp angle bends. That is, heat it until it glows at least dully with a propane torch, then let it cool. Then shine it up again. With copper and its alloys it doesn't matter if it cools slowly or quickly. How to tell? If you make a 90° bend and the piece snaps, then it needed annealing. I don't really remember... but it seems to me it was brass rod to which lead had been added "to make it easier to machine", and which may have been hardened, that needed annealing. That (again as best I recall) was from Metal Superstore (IIRC) as opposed to K & S brass from a hobby shop or #6 AWG solid nickel-silver wire from metaliferous.com .
   I think one can do the annealing before starting to work on the piece. That's when it's still easy to shine up again, and it will be a harder piece once flattened. Only if an initially annealed metal persists in breaking at the arm bends would it need to be annealed after flattening. I don't remember that happening.

After C-clamping this block down, one can stick the key pad end into the hole,
press the metal to the right, and tap it with a hammer to bend/fold the arm over.
(Technicly, to bend everything except the arm over.) The hole depth is
the length of the arm. One may have been used for bending the finger rests.
But I also have a small vise with brass clamps. One end of one is filed
to a bit rounded. I may have used that. It would support the oval arm
better, especially valuable if the axle hole was already drilled in it.



After flattening the wire/rod to an oval shape, I made this jig to help bend the bracket into its several shapes. I don't remember how I used these very well.

  (Just how I bent the curve into the key cap arm I can't remember. It probably involved a hammer, some cylinder piece to bend smoothly around and a clamp, or maybe a vice. One would probably clamp the end of the arm and bend toward the connector section. or... whatever works.)
   Okay, here's a demo with a concave piece and a ball peen hammer. One could get fancy with a couple of forms of decreasing diameters and maybe grooves to hold the narrow part straight.

A technique for bending arms into an arc?

   After all that the bottom surface still won't be perfect for the pad cap and needs to be filed to shape with a semi-round file, hopefully with about the right arc for the top of the cap. And so it goes directly over the top of the hole. And the top shaped too, for esthetics.

Making Axle Tubes

   Again the tubes to cover the axles can be put through arm holes and soldered to the bracket or just slipped on the shaft as spacers. K & S Brass makes telescoping sizes of tubes from very small to about 1/2 an inch. Select the one that fits nicely over your piano wire axle (hopefully from the same hobby shop).
   Nickel-silver tubes seem to be another story. I couldn't find any ready made, so I had to "draw" my own from sheet metal with a "draw plate" - a piece of metal plate of successively smaller holes with tapered entries. I made my own for the purpose. Later I bought one, but IIRC I kept using the one I made because it had fewer holes to confuse me.
   I probably used #28 gauge. One cuts the sheet metal to exact width. Bend it around (somehow) to fit into a wide draw hole. Clamp the draw plate solidly in a vise. Crimp the end so it goes through the hole and use vise-grips to pull the piece through the hole. One then draws it through smaller and smaller holes until it is the right diameter and the ends meet as a seam.
   I don't remember the width for the sheet. I'm sure I used trial and error. The piece should be at least at bit longer than enough for the desired tube, but once the width is known and can be cut exactly, it may be easier to draw a long tube and cut it to lengths later. The pulling needs a lot of pull, but not too much if the hole gradations are fine enough. (I'm sure it's much harder drawing wire, where one is actually stretching the metal instead of just forcing it to bend around.)

The draw plates and some nickel-brass tubes, one yellow brass tube.
Note that the longer tubes aren't closed; there's a gap at the seam
because the sheet wasn't quite wide enough.


Drawing one of the longer tubes through a smaller hole in the purchased draw plate
(smaller than any in my DIY plate) closes up the open seam. But the metal
was cut a bit too narrow, so the resulting tube is too small to fit over an axle.
That's why I never finished and used these pieces.

   Cut off the crimped end that you pulled with. If the tube is bent (it surely will be) or a tight fit over an axle, insert a piece of axle and tap the surface of the tube lightly with a hammer. This will tend to both straighten it, and to increase the diameter by thinning and stretching the metal minutely. Proceed gently, tapping it where it sticks out or binds on the axle until it rotates freely around it. I soldered the first couple of tube seams, but they don't need to hold water and they don't take the twisting force when the key is pressed. The fine seam seems fine without solder, so I stopped.

Forming the Pad Caps (or "Pad Cups")

   These are made out of thin sheet metal usually of the same alloy as the bracket wire or rod. The caps for the G, F#, F & E tone holes are simple round caps. I looked all over to find things that were the desired size and shape. Come on, they're just little round buttons! There were many "almosts", but nothing that actually fit. What was that domed shape I was after?... like, like... a carriage bolt head! I ended up forming all my own caps. Then I had to make special caps and rings for the ring keys as well as for the B-Bb key.

   I formed the caps using carriage bolts as "punches", and larger nuts as "dies". I put the carriage bolt on the lathe and trimmed the edge of the head to flat/vertical at the desired diameter with a file. Then I drilled out or filed out a nut so it fit loosely over the bolt head, with a smooth inner edge, rounded/tapered at the top so it wouldn't rip the sheet metal as it was drawn in. I cut pieces of (I think it was) #26 gauge brass or #28 nickel-silver sheet. (A piece of the brass measured .44 mm [.41 mm is #26) and there was a piece of nickel-silver sheet in the box that said #28 on it in felt pen.)
   So, I would set a small piece of the sheet on the nut, hold the carriage bolt on it, and tap it with a hammer. The sheet metal would be drawn in and take on the shape of the carriage bolt head. (I like the rounded top shape, and the metal conformed fairly easily. One could turn or file the top of the bolt head to a different profile if desired.)
   I only vaguely remember how I trimmed the lower edge of the cap. It seems to me I pounded them far enough into the nut that the metal kind of wrapped around and stayed on the bolt, and then probably I polished it holding the bolt. I think I put the bolt on the lathe and turned it with a hacksaw grinding at the edge until the excess metal fell off. then filed the edge smooth. Or something like that. Eventually I made quite a few extra as shown, so it couldn't have been too hard.


Various pad caps and the "carriage bolt & nut" punches for them,
with a couple of botched attempts. One ripped at the edge; a couple slid to the side or were
otherwise unsymmetrical. Most of them seem to be brass, with a couple of nickel-silver.
(I'm not sure what the largest ones were for - I was making wooden flutes, not saxophones!
Perhaps the punches & dies in the first experiments were larger than I realized.)


A block of "Large Disc Punches" from Stuller's Jewellery Supply:
1/2", 5/8", 3/4", 7/8" and 1.0"
Such punches for thin metal have a top and a bottom plate (center crack just visible),
which are held aligned with each other by the two alignment 'pins' on the left.
The top piece is lifted and the sheet to be punched is slid in between.
Then the punch is inserted and tapped down with sufficient force to shear the metal sheet.
One can easily punch out round blanks for pad caps or whatever.


Ring Keys (Eb, Db)

These were a little different. IIRC I punched the keys that covered the upper tone holes using the punch below. I must have cut the lower rings by hand. I also made two smaller round hole punches for these. One punched out the hole for the rings. The other made indents in the other end of the upper keys to make them into pad caps for thin 8 mm oboe key pads.
   Of course, the keys and rings can be cut and shaped by hand too, and filed smooth. Drill the ring holes first then cut the shapes around them. A step drill bit is a good choice for drilling holes in sheet metal. Twist drills will grab sheet metal and lift it up. (I had a very small bandsaw from Rona (7-1/2 inch wheels) with fine blades that worked well for such fine cutting until it was stolen.)



I made this special shape punch for the Eb-Db keys and rings.
Of course it isn't vital - it's a "faster production" tool.


These are punches I made. The larger one I think I used to punch out
the holes in the rings. Apparently I should have ordered Stuller's
"small disk punch set" along with the "large disk punch set".
(I can't find the die they went into - it wasn't in the box with
all the others. It was probably made from the hex bar as well.)


The B & Bb Telescoping Tube-Key

   One of the features of supercorder that makes it easier to play than other woodwinds is this telescoping pipe plus key mechanism, to play both B and Bb with the right index finger alone. (In transposed terms, F & F#.) The telescoping tube is a bit tedious to make, but I haven't thought of any other way to do it.

   The base of the mechanism is a very short piece of brass "1/8th inch NPT threaded" pipe, The NPT ("national pipe thread") is a fine, slightly tapered thread: the farther it is put on, the tighter it gets. I fear that "1/8 inch brass pipe nipples" are out of fashion for plumbing, but they are doubtless available on line. Just at the end, the inside is drilled out (reamed slightly) to fit a short piece of 5/8 inch O.D. brass tube. (Again K & S Brass from the hobby shop is convenient.)
   Next the threaded end piece is cut off the end of the pipe and the end smoothed off. (On my instrument it's 10 mm long. Some are a bit longer with an unthreaded bit sticking out.)
   With a fine file that cuts on its edge (or ?), make a slot in the top deep enough to hold a flat screwdriver. On the opposite face, a deeper slot. This one is also the guide slot to keep the telescoping tube lined up for the Bb key. The depth of this slot should cause the guide piece on the inner tube to bottom out at the same point that the Bb key closes. If it's too shallow the key won't seal. If it's too deep the tube will keep going down, tilting the key and again losing the seal.

   The wood of the C-B tone hole in the body is threaded with a "1/8 inch NPT tap". The depth of the threads should set the pipe in so it doesn't protrude into the bore. (Here is a place the "thumb rest" comes in handy as it makes the body wall thicker here.) The pipe needs to screw in with the long slot aligned at the top end.

"1/8 inch pipe thread tap"
Note the taper on the threading end, matching that of the pipe nipple threads.
(Mine was just one in a whole set of threading taps & dies)

   I soldered a very short piece of brass rod into the wall of my tube, soldered from the inside. This protruded into the long slot (and no farther) to effect the alignment so the Bb key closed centered on the hole each press. On my instrument I find that after 19 years the left and right edges have worn down a bit, and so the key can move side to side too much, making closing unreliable.
   Owing to this I suggest using a rectangular piece instead. Or (simpler?), a round rod piece that is a little too big in diameter, and file down the sides to flats before soldering it in.



    The tube surround, lever and Bb pad cap I sometimes made from one piece, sometimes using one of the pad cups. These (as best I can remember) were all cut and shaped by hand. An 8 mm clarinet pad seems good; use 8 mm oboe pad for thinner.
   Recently I tried a 10mm pad. It seemed better because with the key having a bit of side-to-side play, the 8 mm pad could be off to either side enough to leak if pressed with twisting pressure.


    At first I cut the slot in the pipe from the bottom. It does the job of preventing the key from popping off. This particular tube stops when the spring is fully compressed, which is just about the right point where the Bb key closes. Great!...
   It made a great little assembly, but it couldn't be disassembled unless one can un-solder the little side pin. (Easier said than done, I find.) Or unsolder the whole top from the tube. I also had to un-solder the pad cap before I could unscrew it from the instrument. And I couldn't get it onto the instrument I usually play even with the pad cap removed. It hit the body wood a couple of turns too soon.



  So I started cutting the pipe slots from the top. Then, to keep the key from popping out, I soldered a springy piece of brass into the tube, diagonally across the hole, to catch on the bottom of the pipe and hold the key in. The spring could be pushed aside with a small screwdriver to disassemble the key. But I've had the key pop out accidently. I confess to never being really happy with that arrangement.

    The tube surround, lever and Bb pad cap I sometimes made from one piece of thick sheet metal, sometimes using one of the pad cups. These (as best I can remember) were all cut and shaped by hand. I probably punched or drilled the hole for the tube first. I was using an 8 mm clarinet pad (or an 8 mm oboe pad for thinner).
   Recently I tried a 10mm clarinet pad. It seems better because with the key having a bit of side-to-side play, the 8 mm pad could be off to either side enough to leak if pressed with twisting pressure.



   Okay, something new! Being unsatisfied, I've just worked out a new way: screw a retainer piece to the body of the instrument that covers the top of the slot in the pipe. (The screw is 2 mm x 6 mm.) It could be made as I've done this one, or with a slot so that it pivots one way to keep it closed and nearby direction to open the slot to remove the key. Or (tolerance being tight) it could be a "washer" with an off-center hole, to be rotated until it covers the slot without rubbing on the tube. There's not much room, but it seems better.

   Maybe better, the screw could be to one side on the body, holding a lever that can cover or uncover the slot. If the lever can be moved by hand that would make it easy to pull the tube out to grease it. To keep the tube from leaking air I goop it up with cork grease in preference to oil.


The pieces of the key.
Opposite to the slot in the pipe is a short slot. A broad blade "screwdriver" can
be made from sheet metal to go between the slots to screw and unscrew the pipe.
(Hmm... would a dime work? ...It would if the second slot was made a little wider.)


I found this little vise, perfect for holding tubes, rather recently on AliExpress.com
(I don't have room to mount most tools permanently on benches. I just got lots of C-clamps and I C-clamp
them on when I need them. Some are "semi-permanent" - clamped to the bench most of the time.)

Winding Springs

   Springs can be wound from piano wire including the same wire as the leaf springs for the other keys. For these ones, put the bottom end of a 5/16 inch or M8 bolt in the edge of a vise, and trap the end of the wire there as well. Wind the wire around the bolt, keeping the wire taut in its threads. When released it will spring out to about the right diameter. Twist the wire back and forth with small pliers or a diagonal cutter to break it off at the desired point. Pull the ends apart to stretch it to the desired length. The ends can be shaped a bit with needlenose pliers or better, two pairs.


Silver Color for Brass?

   Sometimes, using brass before I found a supply of nickel-silver, I tried to color the brass silvery. One technique was to tin everything with solder. That was ugly. Then I used "liquid tin" from an electronics supply store. That works better but isn't very shiny.
   It's probably better to leave the brass yellow, but then the solder being silvery is a nuisance. One can try to avoid spreading it too much, but it does like to spread. Or file and polish off the excess later. And brass does tarnish. Perhaps one could polish it up and then spray on a coating from a can of urethane? (before putting on the pads.)

Setting Pads Under Pad Caps

   This is best done with heat glue and a heat gun, with the instrument assembled. Cut or extrude a small blob of the glue and put it in the cap. Then put the pad under it. With the glue melted, softly tap the key as if you were playing the instrument, a few times. The melted glue will let the pad settle into place flat on the hole, and harden into the correct position as it cools. (I understand that before heat glue it used to be done with shellac. I've never tried that.)
   Replacing a pad is about the same: heat the cap with the hot air gun (or whatever) and pull the old pad off with tweezers. Add enough heat glue to seat the new pad before tapping it in.

Chapter 6: Making the Porcelain Beak & Block

The Mouthpiece and Fine Tuning (with some history)

   Supercorder has a unique mouthpiece. Where other recorders have a mouthpiece carved into the wood of the head for the top of the windway and a separate block of wood (the "block") for the bottom, supercorder's mouthpiece is separate, shorter, and with a wholly different beak and block shape. The flute that shapes the windway is set into the block rather than the beak part.


   The shorter windway and 'special' mouthpiece shape with a hole through the block allow the fine tuning while playing that recorders lack. (and a lovely vibrato!) More than anything it's the inability to play a note in tune at different volume levels that limits the practicality of playing duct flutes in ensembles with other instruments. (Especially objectionable are endings: Fade endings that drop in pitch sound pathetic, but holding a solid mezzo-forte right to cutoff to stay in tune can seem crass - unmusical.) In fact, I would posit that a perhaps subconscious reason few had previously tried to improve the recorder in other ways is that such an endeavor would seem to be an exercise in futility in the face of the tuning problem.


   One day I read that some bamboo flutes were brought into tune by making a hole in the side near the labium to sharpen the pitch. I made a mechanism, a push-lever with a spring, pressed by the lower lip to open such a hole. This was one of the two special, original inspirations for making the supercorder, along with the dual B-Bb pipe/key. It worked, which was exciting, but it was somewhat awkward. It didn't have a really fine feel that a player wants.


   I thought about making a hole directly closed by the lip, but it seemed like it would be an awfully long hole. Was it even close enough to the labium to work? Recorder windways (for alto size) are generally a couple of inches long, and a quarter circle curve shape underneath. Obviously the curve was just tradition and had no bearing on the sound. Did they need to be so long? I cut that in half to an inch and changed the outside shape to "squarish" so the lower lip could conveniently cover a much shorter hole. It worked! Very nicely!



   I don't remember when I decided to try ceramic for the mouthpiece. Quite early on. It seemed like a good idea. It's dimensionally stable regardless of breath moisture. It never swells or warps. (I had had trouble with a maple recorder I once bought. It played fine for the first little while, then started having trouble. One could actually see the head become elliptical after a while.) Rosewoods (several varieties) are a great woodwind wood with little (and even) expansion, but some people become allergic to having it against their lips. A cedar block might also cause a reaction. With a ceramic mouthpiece, there are no such concerns. (Unless someone is so allergic to a wood their fingers react! I believe this is quite rare. The worst rosewoods for allergic reactions: "There are woodworkers who are allergic to cocobolo [and Cambodian rosewood], and those who are not yet allergic." [but who soon will be if they keep working with it without a dust mask])

   Ceramic however is more brittle, more coarse and is somewhat porous. After having a few ceramic mouthpieces fired at the pottery place I bought clay for "cone 6" fired porcelain instead. The first difference is that in firing porcelain (a substantially higher temperature) the clay shrinks more - around 20% instead of 10%. I made molds for the beak and block, and this means making molds 20% oversize - the mold for the 20 mm O.D. block is about 24 mm I.D. Also neither ceramic nor porcelain fires perfectly evenly (at least it didn't for me), so the pieces have to be perfected after firing. The second difference is that porcelain is quite hard. It will simply dull a file and sand away sandpaper. So pretty much the only method for shaping it after firing is grinding.


   Toward the end of my short flute making career the pottery place had a used "mini kiln" for sale, with a regular 120 V AC plug (1500 W). Big enough for making a cup -- or a few mouthpieces and blocks. I decided I could afford 100$ (broke tho I was) and bought it. It seems to me I got better, more consistent results when I fired mouthpieces in this myself. Aside from personal control over the process [and doing a firing whenever I wanted], the mini kiln would heat up and cool down again far faster than the big kilns at the pottery supply shop. That probably gave the pieces less time to sag and warp. (And I'm not sure they shrank quite as much.) It still took 4 hours to heat to "cone 6" to fire the porcelain, with everything glowing white hot. It cooled faster by cracking the door open. (It could barely make it to "cone 6". If I clamped some kiln blocks on the outside with coat hanger wires and put a couple more on top, so it held heat better, at least an hour could be eliminated.)
(I bet one can buy great temperature controlled mini-kilns on line for low cost these days!)

Windway Materials and Sound Character

   Different beak and block materials can give recorders markedly different sounds. Going solely by my own observations and surmise, the reason for this is perhaps surprising. Breath moisture quickly saturates the surface of the material. Particles of moisture in the windway build up, get expelled, or absorbed into porous material, or some combination thereof. One can note that the sound changes from first play until it's "warmed up". As bits of moisture move through the windway, they cause turbulence that imparts a more "reedy" sound character, helping to give them a fuller sound than transverse flute. That this is the reason is demonstrated by the fact that the major change in tone character is in the first tens of seconds of play as the instrument "warms up" and the windway becomes moist.
   With a smooth plastic instrument, water beads up inside the windway in patterns that depend on the notes being played and the breath pressure. Regardless of tonal quality, playing can proceed nicely until an especially high note is wanted. Then, probably with higher breath pressure being required, moisture is expelled all at once and the note doesn't sound. It seems like the player has muffed it. The same high note plays fine on the second attempt. That makes them frustrating to try and play.
   Sound character with wooden windway parts depends on the type of wood and the grain. Generally the moisture sheets more rather than beading up. Cedar is a common block material. It probably sheets and absorbs well, while the upper harder wood may have some beading.
   Unglazed porcelain seems to provide a nice tone. If there is one critique it is that during the transition from "dry" to "saturated", in the first 5, 10 or 20 seconds of playing, there is sometimes a short time where it doesn't sound well and notes may not even come out. (Best to warm it up right before a performance! If necessary one can blow into it while covering the whistle.) I only glazed the outsides of the mouthpiece, with a simple transparent glaze. Sometimes I added a gold glaze to the top of the beak, which glaze is fired later at quite a low temperature.

   Regardless of material, to give good sound and play all the notes, the windway has to be straight, the right thickness, and line up properly with the labium's edge. There needs to be a ~45° top and bottom bevel where the air comes out, perhaps 2 mm long. (I don't know why. Any other angle, a double angle, no bevel, or a rounded exit, makes for fuzzy sound. So does a labium edge that isn't sharp.)

   A critique of Making porcelain mouthpieces is that it is hard to shape them. They usually warp some when fired in the kiln as well as shrink by inexact amounts. Then they are hard to grind, impossible to sand, and will simply dull a file. I found it necessary to make many and find beaks and blocks and then pick out pairs that fit well together. (While writing this I tried a different block in my own instrument and, after a bit of grinding, find it plays the high notes better than the one I've been using all these years!)
   To 'perfect' the 45° bevel in the exit to the windway (both beak and block), about a 2 inch diameter by 1/2 inch wide grinding wheel in the drill press or lathe seems to work pretty well. It's trickier grinding along the flat area if the windway isn't quite straight. It's hard to not grind the edge of the convex flute in the block when grinding it.
   As I look at my collection and think about it, the beaks usually fired pretty straight, at least in the mini kiln. It's the blocks that usually need the grinding. Come to think of it, I think I was getting better results in the mini kiln than when I was taking them to the pottery shop to have them fired. Among other factors it heat up and cools down much faster than than large kilns, which the store owner said may take a whole day or two to cool enough to pull the pieces out.


Molds

   I made molds to shape the porcelain beaks and blocks. In coming up with the shape of the beak, I considered how to fasten it to the wood. I made it to be held against the head by the "U" shaped "retainer" piece of brass, which I threaded on both ends and then had to make special nuts for.
   With hindsight I note that the beak's center ridge isn't needed. The beak can't slide forward anyway. And if there's no ridge, the retainer can be bent on the flat instead of on edge.
   In making the wooden beak mold, I added the ~20% size to account for clay shrinkage during firing. I turned it on the lathe and then sawed it in half.




Another view.
Again the second "rib" is surely superfluous.


With inner diameter piece
(3/4 inch pipe joiner fitting was about right for the inside arc shape/diameter.)


The block molds.
The slightly larger one was the size for porcelain blocks.


Another view.

   The mold for the ceramic block was a 3/4 inch copper pipe joiner piece, just slightly larger than the 3/4 inch pipe itself. For the porcelain blocks this was a bit too small, so I pounded a piece of 3/4 inch pipe to a slightly larger diameter. (I know because I can see the hammer marks.) The ceramic one doesn't quite fit inside it. For doing this, one places a hard (eg, steel) 3/4 inch cylinder inside the pipe, ideally one that just barely fits inside. Set it on an anvil and start tapping on the outside of the pipe with a hammer, everywhere and all around. As the metal stretches, the diameter slowly increases. (At some point one must find a bigger piece to fit inside, but I don't think I had to go that far.) I measure the diameter as 26-27 mm OD, ~23-1/2 to 24-1/2 mm ID. (I guess my pounding to shape wasn't perfect.)

   An arc of 3/4 inch copper pipe fits inside to form the flute. I measure this at 37 mm long, with the inner piece 20mm wide. At the bottom it (the outer pipe) is 22 mm long. After I squeezed the clay into this mold, I drilled the tuning hole with a piece of brass tube, which I filed teeth onto the end of so it would drill better. I recall turning it out as well, to minimize the warping of the clay as I pulled. (I probably still had to straighten them up after pulling the tube out. A bit of water might help.) The pipe was about 8-1/2 mm O.D, which also shrinks by 20% during firing. Of course, the larger the hole, the greater the tuning effect by covering it and uncovering with the lower lip. The maker (you!) and also the player may have slightly different preferences, and it would be worth exploring different hole sizes. When players can make choices according to preferences it lends a certain "mystique" and "excitement", adding interest to the whole genre over just buying and playing. Oboe players even make their own reeds to get just what they want and there are workshops on doing so. Different mouthpieces can be had for brass instruments, especially is there variety in French Horn mouthpieces. Here one could make and sell different block and beak sets. Some players would probably want to try out more than one.

Here is a pretty well matched beak and block, from the lower end.
(The 45 degree end grind in the beak should have been narrower to match the flute width.)

Here is a mismatched  beak and block. The beak sagged a bit because the sides spread out a bit before or during firing (probably in pulling it out of the beak mold), and the center of the windway is too narrow. Yet in my collection is at least one block that matches this beak. How well that pair matches the curve of the edge of the labium is another guess, and the labiums are pretty uniform between instruments. In an assembled & properly adjusted instrument held up to a light, one should be able to look along the block and see a thin line under the labium. It's best if it's uniform all the way across. (that's easiest to see with the block in place, beak removed.)


"U" Shaped Retainer Loop

Mouthpiece parts


 Another view

   Ceramic and porcelain of course break suddenly if struck or if pressured the wrong way. I'm sure it would be folly to try to thread some tiny bolt or screw into a porcelain or ceramic part. To stress it at a point with a nut and bolt going through to tighten down also seemed likely to be a good way to break beaks. The best way I could think of to hold a porcelain beak in place without making a high stress point was to make a "U" shaped loop to clamp it to the body. In order that it couldn't slip out I made the beak with a slot. I had to flatten the "U" and bend it on edge to fit it into the slot. The threaded ends of the "U" go through the mounting holes in the head. Because the holes ended up in the curve of the wood, I drilled them out flat with a drill bit I ground to zero angle on the end. (I found some tiny washers to put in as shown.) Then because the ends were recessed, an ordinary nut wouldn't go in - or more correctly stated, there was no way to get a grip on the nut to turn it. So I made "nuts" out of brass bar. I drilled and threaded one end and cut a screwdriver slot into the other. I used #4-40 threads.

   In lieu of some completely different configuration (?) there's at least one way to simplify this: Instead of a slot, the "rib" in the center could be eliminated, since the beak can't slide forward (into the head), only backward. Then the "U" clamp rod could be bent on the flat instead of the edge, or it could simply be left round.
   The special nuts are a considerable nuisance to make too. They are threaded much of the way through so they don't "bottom out".

Chapter 7: Voicing, Tuning, Finishing

Voicing

   The objectives of voicing are to get all the notes playing well, with the best quality of sound. I confess to not getting the latter on high notes for the longest time. A recorder maker making wooden windways has no trouble, and probably could have pointed out my mistakes immediately. Part of my trouble was not believing that slightly warped porcelain could be causing trouble, combined with the fact that porcelain is so hard to grind and shape once fired.

   The left-right curve, and the width, of the flute in the block & beak should match that of the edge & ramp. The beak should match that so that the height of the windway is uniform across the width. Windways usually taper, a bit wider at the entry than at the exit, with a uniform slope. The windway roof and floor should be straight from front to exit. Using pieces of wire and a micrometer caliper to measure the windway height on my own instrument I get about .8 mm at the entry, .67 mm about the middle, and .45 mm at the exit... inserting the wires at about the middle of the right hand side. The left side is slightly thinner than the right - a slight flaw.

   But just before the exit there is a sudden 45° angle windway expansion with a flat face, about 2 mm long, top and bottom. Any other angle, dual angles or a curve to this face will make hissy or fuzzy sound. (I've tried them all! Another part of my voicing problem was thinking a sloped exit with sharp 45° angles was just convenient to file and that it couldn't really be the optimum shape. It does seem to be.)

   The alignment of the windway with the edge is the most critical point of all. Even tightening or loosening the clamp screws may make a notable difference. If alignment is poor some notes may not sound or will be hesitant, generally in the areas with few fingers down.
   Holding the head up to a light and looking into the windway, a very thin line of light should be visible between the edge and the bottom of the windway, with a substantially thicker one above. Block height is set by putting thin shims underneath the block - or maybe it will be reaming out a bit of the wood under the block depending on exact dimensions.

   A sharp, thin edge gives the clearest sound.


Tuning

   For this you definitely want a good chromatic tuner that shows just how sharp or flat each note is. Start tuning from the bottom up with the holes closed. Each open hole will affect the next couple of notes, so you want the holes just below to be already done as you tune the next one. Tuning changes with breath pressure, temperature and other factors so one can only get to a certain amount of precision rather than "perfection". A note that seemed a bit flat on one occasion may seem okay or even a bit sharp on the next. I recently thought my high "D" (and maybe "C") was flat compared to the lower octave, but a tuner showed the high "E" was rather sharp instead. With most duct flutes the player is stuck with the intrinsic flaws and the maker's tunings. With supercorder (not that careful tuning should be at all skimped on) there's fine tuning via the lip hole to compensate and bring chords into tune, even wile playing louder or more softly.

   The tone hole drill sizes were selected to leave the note, if anything, a bit flat, because one can easily sharpen notes by cutting around the tone hole. Flattening them involves filling in a bit of the hole with a mix of cyanoacrylate glue ("krazy glue", "super glue") and sawdust, preferably sawdust saved from making the instrument. As the hole is enlarged, be aware that the upper octave will sharpen more than the lower.
   Typicly (traditionally?), cuts are made with a very small sharp knife (eg, "Xacto" knife), always cutting away from the grain so as not to dig in. This divides the hole into four quarters where the knife is cutting opposite directions to the quarters beside it. But I stopped doing it that way...

   As previously mentioned, I used steel 'dremmel mototool' burrs to enlarge tone holes by undercutting them, reaming them from the inside without enlarging the outside. (The burr has to fit through the hole.) I don't remember if I got as refined as this or if it's actually as useful with burrs as with a knife, but I would think that if the upper octave is sharper, probably enlarge inside toward the top of the hole to help raise the lower one more. If the upper octave is flatter, I would enlarge toward the bottom so as to raise the pitch of the lower note less. I more remember going around the whole inner edge, a bit at a time, to raise both pitches.

   If second octave D and E or C, D, and E are all flat compared to the same notes in the lower octave, consider reaming out the upper part of the bore a bit more with the upper body adjustment reamer. Take it slowly, as it's easy to go too far.


Finishing

   The wood is coated with an oil. I don't remember much about selecting one over another. Some oils are "non drying". Some like (raw) linseed oil are "drying"; they harden like a stain or paint. Peanut oil is considered "semi drying". It's what I selected. I rubbed all my instruments with a cloth soaked in peanut oil, inside and out, all the wood, more than once. (I haven't done it in years now.) The oils protect the wood and help to keep moisture from penetrating it.

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