 The Clarinet BBoard
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Author: Dan Oberlin
Date: 2002-02-06 17:20
The upper tenon on the upper joint of my R13
appears to have swollen, as none of my barrels
will fit on all the way. It seems that the
obvious solution would be sanding the part of the
tenon above the cork. Does anyone know a good
reason not to do that?
Thanks,
D.O.
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Author: ron b
Date: 2002-02-06 17:56
Have never seen wood swell on a woodwind instrument to that degree in that direction, Dan. I suppose, if indeed that *is* the problem, you could remove material.
However... several good reasons NOT to do that are:
1) If you remove body material, then decide later it was a mistake... it's a bit tricky putting material back.
2) It can be done but it's no fun and that kind of repair will decrease the resale/trade-in value of your instrument.
3) Removing material is a last resort procedure that usually is done after Adding material to repair severe damage.
Before jumping to such a conclusion, I'd try several alternatives.
A) First, I'd check to make sure the metal barrel(s) rings are all the way on.
B) Look for foreign matter in the barrel.
C) If the tenon ends have metal caps, check that they're on all the way.
D) Make sure the cork is not binding.
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If all that fails, I'd visit the local shop(s) and find out if they have some boneyard barrels that might fit.
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Author: jez
Date: 2002-02-06 18:13
Don't even think about sanding!
You don't know where the binding is occuring, the barrel may have shrunk, or the tenon may have expanded. Accurate measurement is required. Manufacturers' clearances are usually about 0.2mm with the top of the tenon slightly smaller than the shoulder. You can't hope to reproduce this except on a machine lathe.
If you don't have the equipment to do this, take it to a reputable repairperson.
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Author: Wes
Date: 2002-02-06 19:27
Yes, I've seen this, especially on new clarinets and oboes. This happened on two R13's for me and also on two oboes, Loree and Laubin. Wood changes with environment and time. It has to be fit together with it's barrel or you can't play. If you force the two pieces together, it will be difficult to separate them. I've evenly removed a tiny bit of an eighth inch of the tenon, where it is sticking, with silicon carbide abrasive paper on a thin piece of wood. What else would you do? If you put it in a lathe, there is a possibility that it won't be centered properly and it may be less accurately removed. There is no need to put it back on as the cork pretty much holds it in place. If you have the measurement tools you can confirm that it doesn't fit before you fix it. If this doesn't seem right to you, just take it to an expert repairman and he/she will do it for you as appropriately suggested above. Good luck!
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Author: ron b
Date: 2002-02-06 20:08
Looks to me like we're headed off on a tangent here. Believe me, Wes, my (machine) lathe runs very true and will easily cut less than a thou of an inch. Would I stick Dan's horn in it? Not on your life. Best advice I can offer, additionally, before bowing out:
Take it take it to a repair tech 
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Author: Ken Shaw
Date: 2002-02-06 20:20
You should NEVER sand the tenon. Always enlarge the socket, which is what shrinks. Do this even if the only reason is that a new barrel is a lot cheaper than a new top joint.
Ken Shaw
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Author: diz
Date: 2002-02-06 20:31
Always let your authorised technical repairman/woman do this - if your clarinet is new (i.e. still under warranty) you will void it (the warranty) if you touch it like this.
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Author: Lawrence
Date: 2002-02-07 00:03
I had this problem with and older model Evette-Schaeffer. It occured on every joint. My repairman reduced the diameter of the tenon in his lathe. He didn't seem overly concerned with either the problem or the solution.
Lawrence
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Author: Gordon (NZ)
Date: 2002-02-07 11:05
Ron: In your first post did you have the mistaken (?) impression that the tenon had increased in length. The tenon will not go into the socket completely when the 'body' end of a tenon has swollen so much that it will not fully enter the socket.
Ken: What gives you the impression that a tenon is not capable of expanding in diameter? That is EXACTLY what happens when it absorbs moisture, which it does rather readily through its end grain.
Lathe: Timber of an instrument may be round straight after manufacture but seldom remains so in the presence of moisture. It can easily become slightly oval. I used to use a (metal) lathe but learnt that it is actually quite rare for for the bore to be concentric with the outside of the tenon. If a centre is used in the tailstock to mount the clarinet body then there is considerable risk of turning the outside NON-circular, or having to turn too much off to get it circular. I have made a jig to centralize a bell tenon from the outside of the body using a "fixed steady" but the outside of the body is not necessarily concentric with the tenon either.
So now I sand, or use quicker equipment, to gradually remove the high spots that are causing a tenon to jam. The high spots are readily recognised by a slightly shiney look.
The only time I adjust a socket is if the diameter of the entry end is smaller than the diameter at the bottom of the socket, making a firm fit impossible. However after doing this capping of either or both ends of a tenon is often required to match the new socket diameter.
I agree that any sanding operation certainly needs caution so as not to be overdone.
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Author: Bob
Date: 2002-02-07 14:43
More expert advice you will probably not hear from anyone. Obviously wrong assumptions re what the problem actually is can lead to real trouble. If your horn is out of warranty and you are not ready to take it to(or find) an expert technician in your area...if it were me I would get a new barrel first. Then you might find that a month or two later the new barrel is too loose and the old one fits again. If that doesn't happen then you do need to take it to somebody who knows what they are doing in spades. As a typical player and only amateur technician I would never consider altering the wood myself.
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Author: Don Berger
Date: 2002-02-07 14:44
Hi Dan- You have gotton a lot of good advice. I agree w: Ken Shaw, and have noticed my pro repairer friends in Tulsa being very careful in recorking-sanding-to-fit to stay as clear as possible of the tenon ends. I had a sticking problem which ultimately cracked the bell on an older wood, and, living dangerously, very lightly sanded the tenon instead of having the thin bell socket enlarged, a difficult decision. Regards, Don
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Author: ron b
Date: 2002-02-07 16:13
Gordon -
Yes. My impression, right or (more likely) wrong, was that the corked tenon had expanded lengthwise enough that it would not allow the barrel to go all the way to the shoulder. I know wood instruments do not stay round, to varying degrees. It's just that *I* have never seen one so out of shape that it will no longer fit by altering the cork. I realize I have a lot to learn but I've not yet seen an instrument with tenon tolerances so close as Dan describes, warpage or not.
I have made wrong assumptions before and usually, thankfully, been corrected by knowledgeable BB contributors.
That's why I come here often. I continue to learn so much, from you and others with much more experience and know how than I ever dreamed only a couple of years ago would become availabe to such a [world] wide audience.
Every day I become more appreciative of Sneezy and Mark's effots to keep it up and running for our benefit. I, for one, do not take the opportunity often enough to thank him. Thanks Mark
- ron b -
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Author: Gordon (NZ)
Date: 2002-02-08 12:04
Ron B:
You probably live in a dry climate.
The majority of new clarinets here, particularly Selmer Paris and Buffet, jam within a few weeks, often in all three joints except the mouthpiece (Note, Ken, that this suggests that the problem is with the tenons rather than the sockets!), often so tight that the instrument cannot be fully assembled. After freeing the fit they often return a few months later with more swelling - jammed again.
Incidentally if a CENTRE tenon is more than 0.15 mm smaller in diameter than the socket it is likely to wobble during play, especially if the socket is metal with low cork friction, and I regard it as a fair candidate for metal caps. I make tight-fitting sterling silver bands and form them over into the cork groove (amnd also over the end of the tenon) for each end of the tenon.
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Author: Bob
Date: 2002-02-08 17:26
I certainly second the thanks to Mark. Gordon: I envy your craftsmanship. I am certainly no clarinet technician or even an expert player but I see clarinets with and without tenon end caps. Technically it seems to me that they make a lot of sense but there must be some disadvantage. I get the impression that some feel they degrade the tone of the horn. I also wonder about this; If the wood wants to expand and contract and you put a "girdle" on it then don't you increase the possibility of cracking occurring in some other location? I'm thinkng the answer is "yes" but that these other locations are better able to "contain" the stress without cracking. Egad forming and silver soldering silver strip for a tenon end cap has to be a real trick.
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Author: Gordon (NZ)
Date: 2002-02-09 15:47
If a tenon 'tries' to expand inside a cap the cap is subject to tension (stretching forces) and the timber is subject to compression. Timber can stand a great deal of compression - even considerable compression distortion, and recover again - but under tension it easily splits. The whole idea of the caps is that the timber is never under tension, just various degrees of compression. The tension forces are all in the metal.
I don't think makers would put these caps on their top models if degrading of the horn had been substantiated.
BTW caps overlap the end of the tenon and hence seal at least some of the end grain, reducing water absorption and reducing the swelling of the timber.
The capping work takes me about 20 minutes per strip, but it took some time time to find a source of graduated thicknesses of silver sheet. The typical thickness required stretches the capabilities of most rolling mills. I have now bought my own mill so that I don't have to hunt again.
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