Flute repair...

Flute repair...

    
Flute repair...    20:07 on Sunday, February 4, 2007          

ha-nul
(43 points)
Posted by ha-nul

Okay, so it's not exactly repairing...
One day, I was trying to "tune" a friend's Chinese-made flute because the cork was WAY off. My flute teacher taught me that I could unscrew the "cork cap" and gently tap in the cork in order to "tune" the flute. My friend's flute's cork was too out, so I started gently tapping in the cork. When the cork was almost to the correct spot, I gently tapped it again, and the cork fell out of the flute! Quickly, I put the cork back into the correct spot in flute and screwed the "cork cap" back on. Apparently, as I screwed on the "cork cap" more, the cork went "up" more (being out of place again).

Is the "cork cap" supposed to work this way? And how can I get the cork to stay in place? [The Chinese-made flute is still playable.]


Re: Flute repair...    20:14 on Sunday, February 4, 2007          

Flutist06
(1545 points)
Posted by Flutist06

That's exactly how the crown (what the cap is called) is supposed to work. Generally it's best not to screw with the cork yourself, but if you need to, tighten the crown to pull it upward, or loosen it and then push the corwn back down to push it down. Do not remove the crown and go to tapping. Not only is that likely to dislodge the cork, but it's far more likely to cause damage to the instrument. To get it to stay, you may need to replace the cork. Headjoints taper, which means the bore size changes throughout the length of the head, and the cork likely was not sized properly for where you were trying to move it to. Unless you've been trained in flute repair and maintainance, you really shouldn't be trying to adjust other people's flutes, even to do something seemingly simple like adjust the location of the headjoint cork.


Re: Flute repair...    20:25 on Sunday, February 4, 2007          

ha-nul
(43 points)
Posted by ha-nul

Okay, thanks for information. Next time, I probably won't be doing this (seeing that my flute teacher sort of taught me it incorrectly). Should I just screw the crown until the cork becomes tighter in order to keep the cork from dislodging?


Re: Flute repair...    20:31 on Sunday, February 4, 2007          

Flutist06
(1545 points)
Posted by Flutist06

For now that would be the best option. If the cork actually is in the wrong spot, it should be fixed, which may require replacement, but this should be done by someone trained to do the work. Until that can happen, just put the cork back where it was and don't worry about it too much.


Re: Flute repair...    20:37 on Sunday, February 4, 2007          

ha-nul
(43 points)
Posted by ha-nul

Okay, thanks again!


Re: Flute repair...    20:38 on Sunday, February 4, 2007          

Flutist06
(1545 points)
Posted by Flutist06

No problem.


Re: Flute repair...    22:55 on Sunday, February 4, 2007          

atoriphile
(254 points)
Posted by atoriphile

I think every flutist should be able to adjust the headjoint cork themselves. Really, it's not that difficult!

Also, without seeing exactly what you are doing, I can't say that what your flute teacher taught you is wrong.

The issue here is the cork definitely needs to be replaced. If it falls out when placed in the correct position, it is way too loose!

Now, replacing the cork is usually best done by a trained flute technician.


Re: Flute repair...    05:35 on Monday, February 5, 2007          

ekdavies
(208 points)
Posted by ekdavies

I've seen too many people (including flute players and other musicians) meddle with the cork position in order to tune a flute. Its both easier and avoids encouraging the cork to leak simply to adjust the extent to which the head joint is in the body of the flute. IMHO flutes should be setup such that to play in tune you need the head joint out a couple of mm - this is usually sufficient to play in tune when the ensemble you are playing with have tuned sharp!

Because of the taper, its often the case that if you move the cork further in it will leak. PTFE tape can be wrapped around the cork as an emergency solution. On those occasions when I've heard students play very flat its usually an emnbouchure issue not the flute!


Re: Flute repair...    06:09 on Monday, February 5, 2007          

Zevang
(491 points)
Posted by Zevang

There is another screw, next to the up end of the cork, that has a function of squeezing the cork so it becomes larger, so it fits properly tight in place when correctly positioned.
Maybe it's just a matter of tightening this screw a little so the cork expands a bit.

Zevang


Re: Flute repair...    08:01 on Monday, February 5, 2007          

JButky
(657 points)
Posted by JButky

>>IMHO flutes should be setup such that to play in tune you need the head joint out a couple of mm -<<

Not true. The flute should be setup so that the effective draw is the result of the octave length for the particular scaling. Once that draw is set, LENGTH BEING DETERMINED BY THE OCTAVE LENGTH WHEN COUPLED TO THE PLAYER, the stopper can be adjusted to further trim the resonances which vary from player to player. (Size of embochure hole, riser height, headjoint taper, player's directed airstream angle and amount of lip covering the hole are all variables).

To demonstrate...holding the flute with your left hand repeatedly tap the g key closed with your ring finger to make the tube resonate with a popping sound. Now take your other hand and roll your thumb over the embouchure hole. You will hear the pitch drop as you cover more of the hole. The presence of an airstream and embouchure increases that effect. It is why the tapped note is higher in pitch than a played note.

The stopper position is also dependent on those variable to a small degree. Moving the stopper will not change the pitch as much as it will align resonances in the flute. And since each flute coupled to a player is different, that small adjustment should be made for optimizing performance.

Joe B


Re: Flute repair...    10:28 on Monday, February 5, 2007          

ekdavies
(208 points)
Posted by ekdavies

I was trying to make two points - but with hindsight not as well as I should have. (a) I agree that moving the cork is not the way to tune a flute but it is too often thought to be! and (b) flute players should be able to play at standard pitch with the head joint a couple of mm out of the body.

Obviously for the bottom octave, moving the head/mouthpiece in and out affects the relative length for the lowest notes which use most of the length of the flute less than higher notes. This means that tuning a flute (and any other woodwind instrument) by moving the mouthpiece in/out of the body is a compromise. If a flute was in physics terms a perfect double open ended oscillator then the second octave (and in physics terms all harmonics) would be affected in the same way. However, the use of the stopper or cork means that there are end effects which are not trivial to understand. One way of thinking about this is that the mouthpiece end of the vibrating column of air is not simply at the middle of the hole. Fortunately, the end effects are also quite small and so most flute players do not need to be concerned about them or do anything other than intuitively correct for them.


Re: Flute repair...    19:53 on Monday, February 5, 2007          

JButky
(657 points)
Posted by JButky


Obviously for the bottom octave, moving the head/mouthpiece in and out affects the relative length for the lowest notes which use most of the length of the flute less than higher notes. This means that tuning a flute (and any other woodwind instrument) by moving the mouthpiece in/out of the body is a compromise. If a flute was in physics terms a perfect double open ended oscillator then the second octave (and in physics terms all harmonics) would be affected in the same way.


True but there exists no such animal (and never will) because of the mathematical functions of the harmonic series. It is impossible to have all the harmonics affected in the same way since there are so many mathematical proportions in scaling that change for every note. You can never get a perfect scale from a fixed scaled oscillator serving numerous harmonic functions. You would need a variable oscillating scale capable of instantaneous revoicing. That means at least, tangibly changing physical bore/length ratios for each note, etc. (think of organ pipes)

Quite frankly that is only possible with theoretical physics. The only comprehensible method at present would be using a fourth dimensional time intersection so that individually fixed frequency specific flutes could be played simultaneously utilizing a fourth dimensional interface (time).

OK never mind..I get a little too carried away. Goes back to my high school days in Math club. Time intersection physical mathematics...Hypercubes, turning basketballs inside out, passing a door thru it's keyhole, walking through walls, you know... non-euclidean geometry.

Joe B


   




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