1. Visual Inspection
The flute is looked over for serious problems (bent body, large dents, unsoldered braces). Bent keys are re-aligned.
2. Strip-Down
The flute is completely dis-assembled. Steel pins are removed from the key assemblies so that the keys can be separated. Loose, sloppy keys are swedged (stretched) to re-establish a nice, snug fit. Keys that bind on the steel rods are straightened so that they hinge smoothly. All needle springs are removed and their condition noted. All old pads are removed and key cups are cleaned of all old paper shims, glue or shellac. All corks, felts, plastic tubing, etc are removed from the keys, and all glue or shellac is scraped away to the bare metal. The head joint cork is removed, and the rollers are removed from the low C and B keys.
3. Body Work
Dents are not only unsightly, they can effect the pitch and playability of the flute. So can a bent body. There are special tools used to roll the dents smooth against a steel mandrel inside the flute, and to straighten a bent body. The three sections of the flute, head joint, body and foot joint, must fit together snugly and smoothly. We check and adjust the fit using special tools. Over time, key ribs and body rings can become unsoldered. They must be removed, cleaned, and resoldered.
4. Cleaning
The body and keys are dipped in a special chemical solution that removes the tarnish from the inside and outside of the flute. They are then rinsed, washed with a gentle dish detergent, rinsed again, and thoroughly dried. The insides of the hinge tubes are scrubbed clean with a pipe cleaner dipped in solvent alcohol. All the steel rods and pivot screws are degreased with a clean rag and solvent alcohol.
5. Buffing
The chemical dip removes about 98% of the tarnish from the silver keys and body of the flute. To get that last 2%, and to bring the metal to a brilliant shine, we must buff all the parts using jeweler's rouge and a high speed buffing wheel. Buffing is a dirty process, so after buffing the parts must be washed, rinsed and dried again.
6. Re-Springing
The springs are re-fitted to the body in their proper positions. Any defective springs are replaced with the proper diameter spring. Spring tensions are set slightly "stiff" until the final adjustments are made, later in the process.
7. Re-Corking
All keys are fitted with the appropriate size and type of cork, felt, teflon or plastic tubing. All are razor-trimmed for neat appearance and proper fit. The head joint cork is inspected and, if needed, a new cork is fitted to the head joint.
8. Fitting the Pads
We buy our flute pads from Kraus Music Products in Oregon. They are thin, Lucien Deluxe pads with firm woven felt and yellow (unbleached) skin. The thin pads give a nice, firm seat. They are harder to work with than the thick, mushy pads some repair people use, but, once seated they tend to stay seated for a very long time. We stock every half-millimeter size, so that we can select a pad that fits the key-cup perfectly because the pad will not seat properly if it is too small or too large for the cup. The trill key pads are carefully glued into the cups with a special hot-melt type glue. We stopped using the traditional glue, shellac, over ten years ago because shellac becomes brittle when the temperature drops below freezing. Here in the Northeast, that happens every winter. When the shellac turns brittle, the pads can easily pop out of the key cups if the horn is bumped, even in the case. The synthetic cements are much more tolerant of cold weather. We have not had a pad pop out since we made the switch! The pads for the larger key cups are either screwed in (for the closed-hole keys) or press-fitted with a metal grommet (for the open-hole keys). Either way, the skin of the pad gets wrinkled when it is tightened into the cup, so we must "iron out" the wrinkles. The skin is moistened with water. A flat metal tool is heated over an open flame and then touched lightly to the damp pad and "Voila!" the pad surface is now completely flat. This is essential, because a wrinkled pad will not seat properly against a flat tone-hole.
9. Reassembly
Here's where the fun begins! First, the key assemblies must be put back together and secured with the steel pins. Each key is lubricated as it is assembled. We use motor oil, in several different weights, for key oil. Today's motor oils are the longest lasting, most highly tested and refined lubricants on the market. They work great on flutes! Following a specific order, each key is fitted to the body. Next, we hook the spring to the key and test the action. Each key should be smooth and responsive, and balanced with the others to produce a "feel" for the player. Now, with the key fitted, we check the pad to see where it is hitting the tone hole, and where it is not. On flutes this is done using a feeler gauge made from thin cigarette paper. The pad should "tug" evenly all around the tone-hole. Any place that is not hitting the tone hole is noted and marked. The key must then be removed from the body, and the pad removed from the key cup. Unlike saxophone or clarinet pads that are adjusted by heating the glue in the key-cup, flute pads are adjusted by gluing tiny shims to the underside of the pad. These shims raise the part of the pad that was not hitting the tone hole so that it makes contact evenly and completely. This process of removing the key and shimming the pad can take place several times for each key in order to get it right. A very painstaking procedure! Once it's in the right position, we "seat" the pad, giving it the impression of the tone-hole it covers. Once we're satisfied we've got it right, we go on to the next key until all of the pads are seated. Wherever two or more pads work together, they must be regulated to ensure that they all come down at exactly the same time. This is done either with regulating screws, or by carefully shimming the regulating tabs on the keys. It must be done precisely, or the flute will not play. After regulating, we set the key height by adding or removing cork or felt from the "foot" of the key. Key height determines how much of an opening there is between the tone-hole and the pad. Too little and the flute feels "stuffy". Too much and the pitch suffers. We usually set a flute up to be "medium-open" unless the player gives us a specific request for "close" or "open". Once this is done, we close up all the pads against their tone-holes with special flute clamps and let the horn settle for a day.
10. Final Adjustments and Play Testing
After the flute has settled, we open it back up and re-check all our work, making any final adjustments that may be needed. Then we play it for a half hour or so, checking for even feel, intonation and resistance. If we make any adjustments, we play the flute again to check them. Once we're satisfied that we have it right, we swab the instrument out, put it in its case, and call the owner to come pick it up. We then work with the owner to make sure the flute feels right to him/her. Everyone plays differently a softer or harder touch, classical, jazz, or rock. These variable can effect how the horn responds, so there are often some player-oriented adjustments that must be made. When the player is fully satisfied that we've got it right, the overhaul is complete! Then it's on to the next one...
