Gandalfe, so people cannot mis-construe what my comments mean.
This is difficult in nature in a mechanical sense, a sax is not, this is why the average person with some mechanical capability can do sax repairs from home with simple tools.
To repair these you would have to do a mechanical apprenticeship to start with, you are working with tolerances of less than 0.001" and also accomodating for heat expansion and effects of barometric pressure at altitude.
A sax, your working with a hinge tube with a rod inside with a big soft leather pad hanging on the end, soft is in comparison to a hard surface like a valve in a cylinder head.
I would offer that doing high end saxophone work, both pad seating and key fitting are done to tolerances of .001" as well. Flute and oboe repair uses feeler material that is .0005". My belief is that working with softer metals that flex and other materials that must exhibit some degree of compression in order to quiet the movement makes saxophone repair more difficult, not less. Doing high end overhauls and restorations requires literally hundreds of small decisions about where compromises must be made because the inherent instability of the materials to achieve the best possible mechanical outcomes. This post by my friend Gordon on SOTW makes this point far more eloquently than I can.
Beyond the mechanics of the moving parts of a saxophone, there is an artistic component to repair work that goes well beyond dealing with the instrument as just a "machine". It takes many years of serious study on any instrument to be able to play that instrument at a level at which nuanced differences are detectable and important. Some of these are:
- The feel of the keys (springs) at all tempos and using every possible sequence of fingering patterns.
- The "tonal color" of adjacent notes in a scale.
- The resistance and "feel" of notes in all registers and all dynamic levels.
- The response of notes in all registers when articulating rapidly.
- The quietness and smoothness all fingering combinations found in all keys signatures.
- The intonation of different notes and registers.
An instrument can be made to mechanically "look right", but a musical instrument must also feel right and sound right to the accomplished player. This is why at the higher levels of repair the physical (mechanical) work of the overhaul is merely the first step. A great deal of the work that is equally (and sometimes even more) time consuming is play testing and making nuanced adjustments to the instrument over a period of days. A friend of mine in repair who has since passed away was fond of saying, "It takes more and more to do less and less".