SupercorderMakingInstructions

Building a Supercorder

The supercorder is a modern version of the primitive design of instrument known in most languages as a "flute" with some qualifier (block flute, beak flute, soft flute...), and in English as a "recorder". It was created by Craig Carmichael over the period of September 2003 to late 2006. (If the name sounds ostentatious, my apologies - I had to call it something that didn't sound mundane. And I didn't make up the confusing name "recorder".) It is fundamentally pitched as an F alto recorder with A=440. Improvements and features beyond those of the baroque or earlier designs of the instrument include:

* The lip hole (the beak is specially shaped to allow it) allows fine tuning while playing and hence in-tune playing of dynamics with fade ending notes that don't drop in pitch, plus a lovely pitch vibrato
* With just 7 keys, all the notes are strong and full and in best tune
* Easiest, most logical chromatic keyed woodwind fingering system ever
* over 2-1/2 octave range from E above middle C to five ledger lines C and even beyond
* strong warm sound through the entire lower octave from the bottom E up - slightly "clarinetish"
* more typical recorder or flute sound into the upper range
* Adjustable windway/beak

There are three main areas of craftsmanship involved in building the supercorder:

* 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. (If desired, the mouthpiece might be done with other materials.)

Please note that the author is primarily an inventor and ultimately not an authority or specialist in any of these fields, nor even in musical instrument design or music playing. But he has gained enough knowledge and experience in all of them to understand and converse with such experts and specialists, and to design a fabulous new musical instrument with great sound and improved capabilities.

Cutting the Head and the Body Pieces

These 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. The suggested starting dimension is about 2 inches by 2 inches square for both pieces. So:

Head: 50mm * 50mm * 140mm (slightly longer if the ends are to be squared off on the lathe later)
Body: 50mm * 50mm * 379mm (ditto)

While a real discussion of woodwind instrument woods is beyond the scope of this writing, here are a couple of lists:

Good Woods

Kingwood*, African Blackwood*, Brazilian Rosewood*, Pau Ferro (Brazil - very nice, mine is pau ferro), Cambodian Rosewood*, Cocobolo*, Plum, Pear

* Rosewood family. Some rosewoods may cause an allergic reaction, particularly cocobolo and cambodian. Owing to the porcelain beak making for little wood in contact with the lips, the effects should be less than with wooden beak instruments.

Bad Woods

Maple (bore becomes elliptical, misshapen as it moistens), Ebony (cracks much too easily IMHO), soft woods, coarse grain woods.

If unsure of the art, one might prefer to practice with some cheaper wood before going for a costly one. (For that maple would be a good choice.)

Drilling the Bore Holes

The bore making operations are done while the wood is still square. It would be almost impossible to line up the bore perfectly by drilling inside an already turned piece of wood. Instead, the bore is used to center the piece on the lathe.

The head bore reamer ends at 17.8mm (.703") wide. So the drill for the head bore has to be slightly smaller than that. I don't remember what drill bit I used, but it was probably 11/16" (.6874"). One doesn't want to drill much smaller than the reamer as reaming is labor intensive and my reamers dull fairly rapidly. I drilled them in a cheap drill press, holding the piece of wood from turning with a large crescent wrench. The drill press stalls or slips at a lower torque than I can hold the wrench.

For the body I used three 18 inch long plain twist drill bits (image). The first drill is 1/2" (13mm), which I drilled in to a depth of 223mm (8-3/4"). Since the bore is an inverse cone, that would be too wide for the entire length, but it saves a lot of reaming versus simply using a bit sized for the small end.
   The second bit is 7/16" (11mm), dilled in farther to 266mm (10.45") One carefully centers the outside end of the bit in the entry of the hole so as to keep the bore straight. (One might skip this step and just use third and smallest one after the first - this step is only a couple of inches further cut length.)
   The third bit is 3/8" (9.5mm), which is drilled through until it comes out the end. Again ensure it's a straight bit and center it in the hole entry when drilling. (The first 3/8" bit I got was bent! Enough to throw off the aim.)

   I had a jig I used to get the body bore hole started straight, until the 1/2" bit was quite a ways in. A long straight piece of metal lined up the drill bit and the piece of wood. There were two wooden blocks with 1/2" holes to guide the 1/2" drill in, and some C-clamps. (I can't seem to find it. I have moved since I was making supercorders and the metal piece was too long for the box I put most of the things in.) Of course I used a handheld drill. (Did I put it all in a vise? I don't remember.)

   To drill the 25mm deep socket in the bottom of the head, the micrometer says I used a 23.5mm or 15/16" twist drill. (I always thought that old drill bit from a pawn shop was 1" and I was drilling 1" holes. Was it undersize? I dug it out, scraped off some rust, and sure enough, it says 15/16" on it!) It's a good size. To get the inside edge of the socket square perhaps a forstner bit would be good? But the twist drill centers itself in the bore hole to start the drilling, and being quite broke back then, I just used it. Also, the sloped-edge socket from a twist drill probably makes for smoother airflow if the head is pulled out a bit for better tuning playing loudly, as is often the case. And in fact, the slight additional volume of the sloped edge space doubtless itself affects the tuning. Hmm!

   (Perhaps a better drilling technique would be to drill out the socket first, then center the main bore drill in the dent in the center of that.)

Reaming the Bore Holes

   The exact bore profile is the most critical factor governing the tuning of the instrument. Once the holes are drilled they must be reamed to exact profile. To that end I provide here the most detailed dimensions I can. Of the four reamers in the image, the top two are the regular head and body full-bore reamers, and the bottom two are for making minor adjustments during tuning if they seem to be useful. I made several instruments before I made the second two reamers, and it may be that re-sharpening those changed their profile just enough to matter.

   These reamers are made from mild steel bars which have been ground down to the desired size. In order to get a good cutting profile, the trailing edges are all ground or filed down to a slightly rounded shape to about half way through the thickness so they won't get in the way, but just a little, so that the backside still provides some support to prevent it from cutting "chattering" back and forth. The leading edges are sharpened to a 90° scraping edge. This seems to work well enough in hard wood. Most of them are 1/8" (3mm) thick steel.
   The head reamer is from a scrap 3/16" thick, by 7/8". It is twisted gradually into the head until it just reaches the end, 140mm. The rest is just a handle.

   The body reamer is 1/8" * 3/4" and this one sticks through by about an inch past the end of the wood when the reaming is done. There's only a short handle, and at the end a brass ring has been put on so it can be mounted in a slowly turning chuck for faster reaming.

At times I used a drill or something to twist the reamers into the bores. More often, I put the reamer in a vise and turned the piece of wood by hand.

Save some sawdust in case a finger hole needs to be reduced. (Use waterproof cyanoacrylate glue + sawdust for anything that needs filling.)

Further Discussion of Recorder Bores

Changing the bore profile means changing all the finger holes and probably the length of the instrument. When I made the supercorder, I copied the bore profile of the Joachim Paetzold "Modern Alto" recorder, which was itself derived from a renaissance recorder bore profile, recommended to Paetzold as having stronger low notes by player Nikolaj Tarasov. This instrument was then reproduced by recorder making company Mollenhauer. I bought one and liked the sound and the tuning. The two keys instead of finger holes for low F and F# allowed it to be made longer, much closer to an ideal accoutic length, unlike the typical "chopped off" keyless baroque alto with its very weak low notes. But I did something different: I didn't undercut the windway. As luck would have it, this small reduction in internal bore space at the top end worked out very advantageously for tuning and high notes. It also made for significant changes in the positions of the finger holes.

   After playing my own supercorder for many years, its tuning had deteriorated as the wood aged and had been repeatedly wetted and dried. In fact it had become quite far off. I got out the reamer and ran it around, scraping out just a few fine shavings of wood. I thought, "Ya, like that's going to do anything!" To my amazement it was right back in tune!

Turning the Outside

This is the part that looks so beautiful when the instrument is made from a lovely piece of wood. I am going to assume the reader has turned wood before or can look it up elsewhere and then get some practice.

The finished size of the head is 45mm (1.75 inches) round at the widest point, by 140mm (5.50"). The exact outer dimension is not critical and one should not be afraid to experiment to achieve tonal variation (or even just a desired appearance?). (As I measure I have one head here that is 42mm wide owing (IIRC) to the starting block of wood being a bit narrow, and there have been other variations.) This widest point is at the labium or the whistle opening about 20mm from the top of the wood. The diameter here may seem excessive. It makes for deep sides on the whistle that help give the low notes strength and tonal quality.
   The outside of the head tapers rapidly down to the beak end and gradually down to 32mm to match the body at the outer joint of the tenon and socket.

The finished length of the body piece is 379mm (14.95").
* The top inch (25mm) is the tenon that fits inside the socket on the head to put the instrument together for playing.
* The upper section's outer diameter is bowed inward from about 32mm to 27mm and back up to 32 at 140mm (5.5"). (Counting only this upper section. If the 25mm joint section is counted, the bottom flare would be at 165mm (6.5").)
* The lower section diameter is straight, about 24mm (15/16") diameter with the bell flaring up to about 35mm or as desired.

On some instruments, the 32mm at the lower end of the top section decreased in diameter abruptly to 24mm to make a built-in thumb rest. On a couple of later ones, the diameter tapered gradually entering the lower half to afford the player more thumb support than "straight pipe" but more thumb position flexibility. (Something in between these extremes might be best.) Having this feature is much more important on the supercorder than on other recorders because while he hands move together, it is mainly the right thumb that pushes the instrument toward the lip or loosens it while all the other digits are fingering notes, to close and open the tuning hole to adjust the tuning. (see images)

The outside dimensions of the body determine how big each finger or key hole needs to be drilled to be in tune. A thicker wall (more "chimney height") needs a larger hole. (see later under "Tuning") The "bell" shape at the bottom end is partly cosmetic, but helps block air for the lowest E flat or D (discussed later) when pressed against the leg.

The tenon on the body needs to be turned down to fit easily into the socket in the head. Then the center of the tenon, perhaps 5/8" wide, is turned down still a little further so that a thin piece of cork can be glued on to make it an airtight fit.

Idea: If the final pitch seems to tend to keep coming out sharp, a simple way to correct it for the future might be to make the tenon and socket a little shorter, eg, as short as 22mm instead of 25, adding up to 3mm to the total length without changing anything else.

Once it is turned, it starts to look like an instrument.

Cutting the Beak Space and Carving the Labium

In deciding "which way is up?", one normally orients the grain vertically. So the whistle, keys and holes are made in edge grain rather than flat grain. There are thus two choices for the head and two for the body. One decides which way they look best together.

   On the head the space to attach the beak assembly is obtained by cutting off the top half to 14mm in, forming a 14mm base and an indented vertical face.

The whistle in the supercorder is about 18mm wide, which favors the lower notes and provides very strong sound. Instead of being undercut, the bottom of the ramp simply follows the curve of the bore inside. So it is even more curved than typical "curved windway" recorders.
   At the indented end, measure 11mm around toward each side from the top center. Cut a slot at each mark to form the sides of the labium. (Be sure not to cut too deep. They can be deepened later as required.) They should angle in toward the bore to 9mm on each side for the 18mm labium, and spread outward just a bit toward the lower end of the head. Now start carving out the labium between the two slots. I prefer a gradually curving slope to the labium until it meets the outside face at a very shallow angle about 45mm along from the vertical face. The knife edge of the whistle should be cut to 4mm beyond the indented vertical face. That is, the slot should be 4mm "long" and a curved 18mm "wide".