Loose head joint

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peterflute
Posts: 13
Joined: Tue Jun 02, 2015 2:10 am

Loose head joint

Post by peterflute »

I bought a Fausili head joint when I was in Paris, and since I didn't have my Muramatsu with me, I tried out their head joints with a Mura they loaned me in the shop. My new head joint turns out to be a little loose. I'm using teflon tape to add a little to improve the fit, but that is annoying and the flute maker who sold me the flute said that this will reduce the resonance. I live in a somewhat remote country area, so it's not so easy to just drop in at the shop and show them. There is a good local tech man, but he has had health problems so I haven't approached him, until this week. I asked him if he could expand the end of the foot joint (is that what they call the tenon?) to improve the fit. He replied by telling me a story. He said he has done this quite a few times in his career, and never had a problem until the day a professional brought him his high-end Haynes for a head joint expansion. It seemed to go ok, but when he saw the flutist some time later, the guy said that his flute just didn't sound the same as it did before, and he could only think it was the head joint work that was responsible. The techy said he just thought the guy was a complainer, until he read a well written article on a closed forum for flute techies, which explained how it can be hazardous to expand the tenon, since it might alter the parabolic curves which are the most important feature of the design of the h.j. So, in short, the techy told me I should research this very carefully and ask the people who made the h.j. What they advise ... In any case, he declined to touch it.

Do any of our resident experts have any experience with this issue?

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JButky
Posts: 390
Joined: Fri Mar 27, 2009 8:21 pm
Location: Mt. Juliet

Re: Loose head joint

Post by JButky »

peterflute wrote:The techy said he just thought the guy was a complainer, until he read a well written article on a closed forum for flute techies, which explained how it can be hazardous to expand the tenon, since it might alter the parabolic curves which are the most important feature of the design of the h.j. So, in short, the techy told me I should research this very carefully and ask the people who made the h.j. What they advise ... In any case, he declined to touch it.

Do any of our resident experts have any experience with this issue?
First off, You are not going to change the parabolic curve (kind of a misnomer anyway), The headjoint tenon is not tapered. Your are past any taper where headjoint fitting is concerned

A modest amount of adjusting is generally OK. There are many ways to do it, most will burnish the tenon up to size rather than use an expander.

The differences that are made are explained as such. Flute bores are pretty consistent. Sizing becomes and issue because the thickness of the metal is different than the original headjoint. In your case, the new headjoint metal thickness is thinner than the old, (Bore being consistent), so it is too loose.

The question then becomes, how loose is it? If it's a lot loose, then burnishing or expanding will create a bore mismatch. Burnishing compresses the tenon, thinning the metal further. The same metal needs to go somewhere so the diameter gets larger. Sometimes not a problem, sometimes noticeable when a large amount is needed.

Small amounts are acceptable. But if you have to go a lot, then installing a sleeve to take up the space is the better alternative to maintain the bore profile between headjoint and body tube. There is metal tape which can easily be affixed to the tenon via adhesive and sanded down to fit. If you ever sell the headjoint, the sleeve can be removed preserving the original integrity of the headjoint.

So the question to you is how much does it need to go to fit properly? You'll need a tech to properly gauge that question..
Joe B

peterflute
Posts: 13
Joined: Tue Jun 02, 2015 2:10 am

Re: Loose head joint

Post by peterflute »

THanks for that reply Joe, it's the clearest thing I've heard on the subject, and it makes sense totally. Now that you say the internal diameter is the same on most head joints, but the external diameter changes with the thickness of the metal, I do in in fact see that the metal in the Fausili h.j. Is visibly thinner than that of the Muramatsu. Thus a loose fit is inevitable.

Then it's about how loose. It's loose enough to slide easily on and off with no sideways twist, And loose enough to drop off if held vertically with the h.j pointing down. You can hear the soft bump when you hold the h.j. and the body one in each fist and move from side to side. I also expect that the looseness is the cause of the tendency for the flut to squeek on some of the weaker notes.

Until I can get it to a tech I will try using a very fine sheet of copper wrapped around it. These are sold on-line by a British company. They say you can cut the sheet to length to get the required amount of filling, if one complete turn makes it too thick. Tht sound dubious as it would leave a little space at each end of the sheet. Some experimentation is on the way.

fluteguy18
Posts: 2311
Joined: Sun Jul 16, 2006 3:11 pm

Re: Loose head joint

Post by fluteguy18 »

I know that I'm late to the party, but honestly, Joe's obviously right on the money. The only thing I care to add is if a technician is worried about messing up the taper of the headjoint, then I seriously question their knowledge about joint fitting and headjoint geometry. With various proper techniques and knowledge of headjoint tapers, it shouldn't ever be a danger.

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