Recorder and flute making
Over the last ten years, the expectations of recorder players have greatly increased, constraining manufacturers to make considerable improvements. Nowadays, a high quality instrument must have fast attacks in the upper register, power in the lower register, perfect intonation and refined sound color.
Making recorders is a stimulating experience but demands infinite time and painstaking accuracy.My workshop is rationally designed and well equipped, so I can create my instruments with great flexibility : I can switch from making a Rafi Tenor recorder to a Baroque Soprano with ease.
I control different aspects of my work with various optical instruments ranging from a watchmaker's loupe to a stereoscopic microscope.
Sharpness of cutting edges, surface texture, porosity of different woods... so many details that appear in a very different light. This is a good example of my approach to violin making.
Nothing is left to chance, whether it is the brand of abrasives I use, the immersion time in drying oils, the steel grade of my tools, the sharpening processes, etc. ... everything is tested, controlled, and regularly revised.
The design of the instrument is the first phase.
Many different fingerings and pitches have been used during the history of the recorder. For practical reasons, the pitches most used today are 415 and 440 Hz. The 460 pitch applies essentially to Consort Renaissance recorders, used for a specific repertoire. The most common fingerings are the Baroque, the ancient (or Hotteterre), and the Ganassi fingering (similar to the ancient fingering on the first octave and a half).
Because of this multiplicity of fingerings and pitches, more often than not the recorder maker must base his work on historical models. Some of these were measured and drawn with great care by their manufacturers. Fred Morgan, especially, left us extremely interesting, precise and detailed plans.
The conversion of the pitch is done following very simple homothetic mathematical relations but there is an inevitable modification of the tone of the instrument. Often, the fingering has to be adapted. Modern fingering (erroneously called Baroque) is unfortunately unavoidable today. Since recorder fingering has changed so often during the history of the instrument, was it really necessary to invent this one? I would have preferred to keep the Hotteterre fingering, since it facilitates playing on instruments nearer to the originals, but modern fingering is so widespread today that it is unlikely to be abandoned.
The tessitura sometimes needs to be increased, as is the case with the Ganassi recorder, or with Renaissance recorders. Sylvestro Ganassi included in his treatise a fingering tablature for a recorder with a very large range. It therefore seemed legitimate for musicians to demand such an instrument. However, since this range was not entirely used in the examples of diminutions which followed, we presume that it was not playable with so much ease. The makers were therefore led to make this recorder usable over two and a half octaves, but ultimately without any real historical justification.
Another problem is the temperament. Our modern ears are used to the homogeneity of the equal temperament but unequal temperaments bring a color and unique expressivity to instruments, even in solo works. The electronic tuner is a precious aid but should be used with precaution. I advise all musicians to use this excellent tool with circumspection. By its use, we have compelled manufacturers to come nearer and nearer to using equal temperament, which presents little interest for a recorder. Deviations of 35 cents between two notes (C sharp and E flat for example) can be found on a perfectly tuned flute with Mesotonic temperament. Among the best known, the most moderate temperament is Valotti, which I recommend to you for baroque instruments if you are a novice.
Once the design is complete, the actual manufacturing process begins.
The wood used must be left to dry for four or five years, more if possible. The ideal is to have a stock of wood cut or bought by a far-sighted parent. Happily, my father assembled a stock of boxwood, maple, pear, African blackwood (grenadille), Brazilian rosewood and bubinga during the years 1975 to 1980. Of course, I renew this stock regularly for future use.
But the drying time is not enough. I place particular importance on letting the wood rest for a few months between the various phases of production: roughing, drilling, turning, and finishing are operations that can be spaced two to three months apart. The boxwood undergoes a specific treatment: it is immersed in hot oil to complete the drying process and eliminate the internal tensions that have accumulated over time.
The cutting is carried out using a band saw. A rigorous selection of parts is already made at this stage.
The corners are knocked down before turning.
Rounding and length adjustments are carried out on a numerically controlled lathe to ensure good precision in terms of the part geometry. This will simplify drilling and boring operations, allowing for a better result.
Drilling is the next step. To ensure better centering, the piece of wood rotates and the drill bit remains fixed. A first cylindrical hole is made with a tool capable of removing large amounts of material, such as an air drill.
With this type of tool, precise drilling can be done without generating heat as the shavings are progressively evacuated by compressed air.
Finishing is done with a special cutting tool called a "reamer". Unlike the classic helicoïdal drill which cuts at its extremity and can therefore only make a cylindrical hole, the reamer has a cutting blade along its whole length, making a conical hole with a excellent finish. The reamer reproduces its own shape inside the drilled hole, thus making it possible to obtain a bore of complex form. A different reamer is required for each inside profile. Reamers are very important tools, specific to the manufacture of wind instruments.
I make mine in my workshop where they are turned on a high-precision CNC lathe. The cuts are trimmed with a milling machine, a machine that provides great service in a workshop.
The result is a rough cut close to the final objective which gives me a good foundation on which to work.
Turning is done by hand for some instruments or with a digital command lathe for others. This complicated machine executes work of such high quality that one forgets how difficult it is to operate. Whether or not it is done by hand, turning creates the aesthetic appearance of he recorder but the actual creative part, which gives the instrument its individual sonority, comes much later in the process.
Polishing and dyeing give each instrument a unique character. Finer and finer abrasives (up to 1200 grit) are applied successively, then the piece is finished with a polishing paste. The final result depends in part on the sharpness of the tools used for turning.
Simple-shaped flutes like Ganassi and Rafi can be varnished "à la française" with shellac, especially if they are made of light wood and are not stained. As for more complex-shaped flutes, like Baroque flutes, or made of darker wood like Grenadilla, they are simply polished.
In all cases, the recorder is treated with sicative oil to improve its acoustic qualities and to limit exchanges of dampness with the air. The dyeing is carried out in the traditional way, with nitric acid, among other things, following a strict preparation and finishing process. This type of dyeing has shown extraordinary resistance over time, since historical instruments were dyed this way.
The window is cut on a milling machine, the head of the flute being held on a special support.
I have a 4-axis controlled milling machine that allows me to perform various operations, including drilling body holes. While the machine is for sure overqualified for this operation, it has the advantage of offering great precision, particularly in angular position. Failing that, one can trace the holes centers and use a traditional drill press.
I also make excellent rough cuts of blocks for the most common models with this machine.
An excellent result with a nice, clean cut. 
From this moment on, lathes, drills and other machines are set aside. Now we have the most time-consuming and interesting part of the work which I do at my desk with simple traditional tools.
The labium is finished by hand with a wood chisel and special tools.
It is precisely fitted into the head of the flute so that it can be fitted without forcing with a perfect seal.
The windway is worked with fine abrasives and the window finished with diverse small tools like fine files and scalpels.
The scalpel is also used to flare out the holes of the body and foot, which is one of the methods of tuning the recorder.
Some types of wood are sensitive to humidity in the first few hours of life of the instrument and require many adjustments before the wood settles down and stabilizes.
Some aspects of the finished recorder can be judged objectively: ease in the higher register, stability in the lower register, the pitch. But the sonority, the ease of interpreting the musical intention and the comfort of playing are much more subjective. This is when the recorder maker can become really creative, as he models the sound and personality of the instrument. The regulation of the beak is a work of great finesse, which requires delicacy and patience.
The recorder is played, tried out then adjusted as often as necessary until it becomes a unique instrument facilitating easy musical expression and giving the player a real pleasure.
