 The Clarinet BBoard
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Author: Garth Libre
Date: 2014-02-24 02:41
I purchased a sheet of 1/16 cork from Music Medic for less than $8 delivered (enough to do 8 to 10 tenons). Armed only with the knowledge I could glean from a few youtube videos, I quickly was able to remove the old cork and residue using nothing more than a slip joint pliers and a touch of soap and water with a tiny brush. It was easy to cut a strip of cork, bevel it and apply the glue to both surfaces. Ten minutes or so later, the cork was on and secure, and I was filing away to bring down the thickness. I sealed it with a touch of candle wax and afterwards some cork grease. Done!
If I had it to do over again, I would have filed less cork away, as the addition of the wax and grease made the fit perfect and I suspect I should have left it a little tight to allow for initial compression. Live and learn. In any event, I learned something valuable, damaged nothing and saved between 10 and 20 dollars.
Garth, 305-981-4705. garthlibre@yahoo.com
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Author: CHUCKO
Date: 2014-02-24 08:02
Get yourself some 3/64 cork next time and you won't have to sand as much.
Also a tenon sizer/straight edge from Ferree's is a great time saver.
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Author: kdk ★2017
Date: 2014-02-24 08:13
Tenon corks are probably (without meaning to minimize what you accomplished) one of the easiest clarinet repairs to make as a DIY project. The result really doesn't affect anything else on the instrument, so a discovery like "I should have left it a little tight" is easy enough to deal with - if it's loose enough, you can always re-do the job.
Pad replacement is not difficult, either, so long as you understand that just getting the pad cemented into the cup isn't nearly the whole job and that the pad must seat evenly in order to provide an adequate seal. It gets trickier when the pad is part of a series of interdependent mechanisms and incorrect pad thickness can interfere with another key's ability to close. That isn't hard to learn, but you're better off having someone teach you good technique than trying to figure it out from pictures and videos.
Things like tone hole repair - truing and smoothing the pad seat so a new pad is able to seal - is something a good tech may be able to do better. Fitting keys to prevent them from binding or to improve the action's efficiency are things that, if done poorly, can have serious consequences that are more difficult to undo than a too thin tenon cork.
So the most important thing that a non-expert DIYer needs to know is when DIY may become OMG and someone with repair training and experience would do a more reliable job.
Karl
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Author: clarnibass
Date: 2014-02-24 10:00
How tight the fit should be before applying grease is something you learn from experience.
I never use 1/16" (1.6mm) thick cork for tenons. If more than 1.2mm thick is necessary then I add a layer of something else. Otherwise I usually consider the cork is too thick.
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Author: Wes
Date: 2014-02-24 10:21
I keep 1/32, 3/64, and 1/16 inch cork on hand for tenons, often using the 3/64 cork. It's easy to do!
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Author: Caroline Smale
Date: 2014-02-24 19:01
The optimum thickness of cork needed for any specific tenon is dependant very much on the difference in diameter between the bare tenon slot and the socket.
A good starting point is to choose cork thickness between 75 and 100% of this difference.
However the quality and resilience of the cork also come into play here and much commercial cork is often lacking in these areas and so the cork needs to be thinned down more in these cases.
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Author: Gordon (NZ)
Date: 2014-02-24 21:27
Another factor though... The firmness (hence friction) of the cork is what stops the centre joint of a clarinet from wobbling when the fit of the timber shoulders is otherwise quite good.
If the cork groove is exceptionally deep, so that unusually thick cork is needed, then that cork will probably not be firm enough (on account of its thickness) to provide anti-wobble.
But as Clarnibass has indicated, if the groove is deep enough that unusually thick cork is needed, it is better to first reduce the groove depth with a firmer material such as "techcork", before corking in the usual fashion.
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Author: Chris P
Date: 2014-02-24 22:39
Instruments with metal sleeved sockets require a thicker tenon cork due to the smooth surface they're in contact with which isn't as 'grabby' as a wooden socket (which is very rough at a molecular level by comparison), likewise with plastic instruments. The thicker tenon cork will apply more pressure to the socket which will ensure the joints will stay put once well greased.
The best type of tenon slot is a reasonably shallow one (around 0.5mm deep to a maximum of 1mm deep) with a completely smooth and flat surface for the cork to adhere fully to using modern adhesives (Evo-Stik and the like).
Grooved or wavy tenon slots aren't good with modern adhesives as there won't be full contact with the cork strip so there will be small contact points with the cork strip and voids in between.
Back in the dark ages they turned grooved tenons to provide a larger surface area when the ancients used shellac to glue tenon corks on with, but that archaic practice fortunately died out along with the dinosaurs (likewise using shellac to glue key corks on with).
YET THERE ARE MANUFACTURERS WHO STILL INSIST IN USING DEEPLY GROOVED OR WAVY TENON SLOTS. YOU KNOW WHO YOU ARE, SO STOP THIS NONSENSE NOW!
Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.
Post Edited (2014-02-25 03:42)
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Author: Gordon (NZ)
Date: 2014-02-25 15:46
"YET THERE ARE MANUFACTURERS WHO STILL INSIST IN USING DEEPLY GROOVED OR WAVY TENON SLOTS. YOU KNOW WHO YOU ARE, SO STOP THIS NONSENSE NOW!"
I totally agree. It just puts a flag up - Clueless factory!
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Author: Garth Libre
Date: 2014-02-25 10:52
I used contact cement on a Selmer B* mouthpiece which had deep grooves. Does that mean the cork will soon start to slip? Should I have used some other glue?
Garth, 305-981-4705. garthlibre@yahoo.com
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Author: Caroline Smale
Date: 2014-02-25 19:10
No - contact glue is the best option.
In fact as the cork is compressed by insertion in the socket then the side of the cork against the tenon will start to expand into those grooves anyway.
If you inspect the lower surface of the cork you removed you will probably find it has taken the exact shape of those grooves.
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Author: Gordon (NZ)
Date: 2014-02-25 19:15
It is the deep waves that I am talking about. I don't think you see this on a mouthpiece.
Cross section is like a wave-form - 3 or 4 mounds and 3 or 4 troughs. Where the troughs are, the cork is too thick to serve much purpose at all. I'd say that the troughs are at least 2 mm less in tenon diameter than the mounds. The concept is utterly pointless.
If the tenon groove is marked with some very narrow circumferential cuts, as seen on other clarinets, this too, is pointless, but has little or no effect on the tenon cork's function and adhesion.
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Author: MichaelW
Date: 2014-02-26 00:12
In the dark ages tenons had grooves also to hold the coiled thread gasket. With my old instruments where I make thread gaskets I am still glad for them as they make coiling more durable. And till now I haven’t observed that cork with contact cement holds less on a grooved tenon.
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Author: Chris P
Date: 2014-02-26 11:47
You'll find that when it comes to removing existing tenon corks, the majority of them peel off very easily when fitted to tenons with deeply grooved or wavy slots.
While the grooves/waves provide extra surface area for adhesives, they also provide minimal contact area with the tenon cork which only makes contact with the peaks. Unless you've got something to replicate the deep grooves or waves on the cork strip so they mesh perfectly with the grooves/waves cut into the tenon slot, then and only then will you will benefit from the maximum surface area when both parts come together.
But that's highly unlikely, so the only course of action is to either remove the tenon grooves/waves by turning them down and stick an extra piece of rubco in the slot to make the slot shallower and glue the tenon cork over that, or fill in the voids in the grooved/wavy tenon slot with carbon fibre (which will also add strength, especially to the thinner walled lower joint tenon if there's no tenon ring fitted) and machine it flat for maximum contact with the other flat surface of the cork strip.
Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.
Post Edited (2014-02-26 06:51)
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Author: Tony F
Date: 2014-02-26 14:05
When I come across a deeply grooved tenon I generally remove the grooves on the lathe using a whiffler file and use slightly thicker cork. The joints fit well and it doesn't seem to make any difference in the wear time. I note Chris's use of carbon fibre, and will try it. Thank you, Chris.
Tony F.
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Author: Chris P
Date: 2014-02-26 14:30
Non-Prestige Buffets and others without metal tenon rings fitted will definitely benefit from the added strength of carbon fibre banding, especially on the lower joint tenon - also alto and bass clarinet tenons that aren't reinforced with a tenon ring as the tenons on these are thin in relation to the much wider diameter of the joints.
On boxwood and more importantly on maple-bodied instruments (eg. bassoons), thread lapped tenons (as previously mentioned) give thin tenons the much needed strength that a glued on cork strip doesn't provide, so on lower joint tenons on clarinets a combination of carbon fibre banding and a tenon cork gives the best of both worlds - a strong tenon and also a perfect seal with the tenon cork.
The tenon cork is fitted to act as an air and watertight seal provided it is sufficiently greased, plus it's also there to provide the necessary outward pressure acting on the socket to keep the joints held firmly together.
I fail to see the benefits of tapered tenons and sockets - to me, a parallel sided socket with a well fitting tenon is the best solution to any jointed woodwind instrument. If you have tapered tenons and sockets, they'll only be a good fit when the wood of both tenon and socket fully meet which means you have to have the joints fitting perfectly and anything less will result in wobble. If the socket ring is slightly proud of the top of the socket (due to the extra thickness of silver plating, etc.), then this good fit is compromised
Parallel sided sockets and well fitting tenons act like a slide joint (remove the tenon cork out of the equation for the time being), so there is full contact with each other no matter how far the joint is fitted together - add to this a much wider upper tenon ring to ensure the tenon is fully supported by the socket even when pulled out by around 3mm.
Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.
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Author: Caroline Smale
Date: 2014-02-26 16:00
The only woodwind to benefit from tapered sockets in my experience are bassoons where the long joint and bell joint tenons apart from being quite fragile also need to be easy to assemble yet firm once fully in place.
Like other posters I usually use a file to reduce the wavy grooves found on Buffets of a certain era. However in my experience of replacing many thousands of tenon corks I have yet to find one where the old cork has not expanded to fit the profile of the underlying tenon. I would imagine that could only happen if an extremely thin cork was fitted in the first place.
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Author: BartHx
Date: 2014-02-26 23:03
I tend to like older instruments and did not come across a wavy tenon until I replaced the corks on a Selmer 10G. My solution was to clamp the cork tight enough to force it to follow the wavy surface. This transferred the wavy pattern to the surface of the cork, so I used slightly thicker cork and sanded it flat after the adhesive was completely set. The only problem was that, by following the wavy surface, I had to cut the cork slightly wider than the tenon groove. The one cork strip that I cut a little too wide I was able to set one edge flush and trim the other edge with a razor blade after it was clamped and before the adhesive had completely set (I do use contact cement).
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