 The Clarinet BBoard
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Author: Avie
Date: 2005-11-20 16:02
I did a repad on the lower joint of my 68 Buffet and discovered that the lower joint keys would not play unless I pressed on the G# D# pad. I dont know if I detentioned the spring or possibly the pad height is lower than the previous pad that I removed or possibly just an inferior pad that I ordered over the internet. The previous pad had a spacer under it. I didnt want to have to replace the spring unless absolutely necessary and I would have to order another Pad in order to replace the existing pad with a spacer. Furthermore Im not sure that would work either because the existing pad doesnt open much now and a lesser gap may distort the tone in the open position. So this is my dilema. Any thoughts or opinions would be much appreciated. I looked on the search feature and saw a similar problem and excellent suggestion posted by Gordan concerning the same G# D# key as how to replace the pad and not to detention the spring. The G# D# key on my instrument has to be pinned together with the C key which also has a short spring is in position but doest seem to be a problem. Unfortunately there are no techs in my area. If its the spring, where would I purchase it from? Any thoughts, opinions, Gordan, anybody would be much appreciated. Thanks. Avie
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Author: Paul Aviles
Date: 2005-11-20 16:45
It sounds as if you say there is not much open space now with the new pad and the key open. If this is true the new pad may just have been too thick in the first place. A thick pad will make the cup sit at more of an angle than it should when at rest. That would make floating the pad into the right postion even harder. Unfortunately, once a pad has taken on a ringed crease, it is usually not possible to readjust the same pad and get it to work.
You also mention the spring tensions in an unusual way. The best way to get the springs on and off without "detensioning," is to carefully pull them out of the notched flange just enough to set them free using a standard crouchette hook. If the spring is indeed too lose, it is an easy matter of bending the spring with needle nose pliers (gently, a little at a time, at a point about a fourth or third of the spring's length from the originating post).
I suggest working on a junk clarinet that's just gathering dust somewhere first just to get the hang of it. But this operation is not too hard and is reversable if you kinda gum things up the first time - you just may need more pads.
............Paul Aviles
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Author: Gordon (NZ)
Date: 2005-11-20 20:07
The most important part about changing a pad is choosing one and installing it in such a way that it closes with even pressure all the way around the tone hole, tested with a feeler (and perhaps some experience!)
The first question to ask is whether you KNOW that you achieved this.
(The fact that it used to be packed out suggests that it actually NEEDS quite a thick pad, or a lot of packing - preferably glue - behind the pad, in order to make it close correctly at the 'back' of the tone hole. )
The second question to ask is if you are de-tensioning the spring while you are fitting the key. Id so, then no amount of changing springs will correct the problem.
Paul wrote "You also mention the spring tensions in an unusual way. The best way to get the springs on and off without "de-tensioning," is to carefully pull them out of the notched flange just enough to set them free using a standard crouchette hook. If the spring is indeed too lose, it is an easy matter of bending the spring with needle nose pliers (gently, a little at a time, at a point about a fourth or third of the spring's length from the originating post)"
Sorry but I totally disagree. Avie, as I think I explained in the article you referred to, if the key is already mounted, then even that tiny extra pull needed to get the spring carefully over the spring cradle 's lip is enough to de-tension the spring sufficiently for it to operate with insufficient force. This is particularly true if the spring is working right to its "elastic limit' during normal operation, which is likely to be the case for every spring that that has a small length-to-diameter ratio.
As I wrote in that article, to maintain the tension in the spring during the installation of the keys:
1. Re-tension the spring(s)
2. Position the keys on the instrument, with the G#/D# pad touching its tone hole, but displaced in a direction so the spring cradle is closer to the end of the spring, say a millimetre. If anything, the F/C key should be in an open position and displaced in the same direction as you displaced the G#/D# key/pad.
3. Hook on their respective springs with a crochet hook, being VERY careful not to pull them any further than is absolutely necessary to get them into the spring cradles.
4. NOW, Very carefully slide the keys back to alignment with their supporting posts, being VERY careful not to pull them any further than is absolutely necessary to get the pivot tubes in line with the posts.
5. Replace the pivot rod (with lubrication).
6. If the spring tension is too GREAT, pull the end a tiny amount - usually a fraction of a millimetre - towards you, away from the cradle, using a crochet hook. Allow it to return to the cradle.
The spring needs replacing only if:
1. It has rusted significantly near the base - enough to weaken it.
2. It has fractured or partially fractured.
3. The heat treatment of the spring was poor, such that the elastic limit is too low.
4. The heat treatment of the spring was poor, such that the spring will break before it is given sufficient "pre-tension".
5. Somebody has overheated the spring, wrecking its heat treatment.
6. Somebody has installed a spring that is weak compared with the original.
Two other possibilities that could cause your problem come to mind:
1. The spring is insecure in its mounting.
2. The post is either wobbly, or is too loose, such that it has rotated. When a post rotates or is loose, it both points the spring in a different direction, equivalent to de-tensioning it, and also may bind against the end of the pivot tube, such that the spring is not strong enough to adequately overcome this added friction.
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Author: ron b
Date: 2005-11-20 20:41
This certainly sounds to me, the way you describe it, Avie, like your pad is not seating all the way around, as Paul and Gordon have already said. The 'problem' I most often discover when re-adjusting a stuffy clarinet is that that pad in particular has an awful reputation of not being well seated in back. Maybe because it's very difficult to observe that area when using a leak light and not the easiest place to reach with a feeler. The geometry of the key is also not as "forgiving" as the rest of those big bottom keys. Many techs almost automatically "sense" this problem and correct it right away before doing anything else.
Then, if you find your spring to be the problem, Gordon's advice is the best you'll find anywhere in the world 
- ron b -
P.S. --
It's possible to re-pad that key without removing it but we may not want to get into that here at this point. It's a quick-fix, true, and a bit 'trickier' than the usual method but you needn't bend anything while you're at it.
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Author: Paul Aviles
Date: 2005-11-20 20:54
Dear Gordon,
I wish I'd read your earlier article. It may have prevented me from setting a brand new Mirimatsu on fire - one brief, shining moment.
I have recently had an issue with that very post to which you refer being loose on a clarinet. The spring does "weaken" because the post is twisting in the opposite direction but it is my experience that the key rotates about the pivot tube much like a door hinge and not the other way around.
I have two sincere follow up questions since I am "home schooled." When you foat in the pads, do you re-apply heat after mounting on the horn to get a correct seat? Wouldn't lacquer be better if only because you can SEE it if there is any smear around the working part of the pad? I have experienced clear glue in a not so positive way.
..........Paul Aviles
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Author: Avie
Date: 2005-11-20 23:16
Thank you all for your sugestions. I have bent the needle springs slightly and seem to be getting fairly good pad pressure and now the E and F plays in the lower reg. but just barely. Some success but all other notes play except I cant get B & C in the upper Reg. over the break to play at all. As suggested It could be the pads not seating well enough on the related pad holes since there seems to be enough spring pressure now. Maybe I will experiment with the height of new and possibly a better quality pad. Any suggestions? What ever my hats off to all you techs for your patience and advise. Avie
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Author: tictactux ★2017
Date: 2005-11-21 00:38
That exact key is bothering me too - it's tight though, but when I do the cover-all-holes-plus-the-lower-end trick and blow, that key is the first one to "lift off".
Looks as if the spring force per pad surface is lower than with other keys that normally are closed. It has always proved to be the trickiest to repad (on two clarinets so far, I'm still a rookie). I needed a very thin cork wedge between cup and pad to compensate for the slightly awkward angle. Fortunately the glue I use dries rather slowly, giving me plenty of time to reseat (and disassemble and start from scratch if unavoidable) till happy.
With Gordon's priceless hints it takes only half as many attempts to do it satisfactorily, a heartfelt "thank you" to NZ.
--
Ben
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Author: Gordon (NZ)
Date: 2005-11-21 03:36
Paul:
"... but it is my experience that the key rotates about the pivot tube much like a door hinge and not the other way around."
I'm not sure what you are getting at here. I agree with your experience. Perhaps you did not notice that that I wrote that binding may take place between the turned post and the END of the pivot TUBE.
"...When you float in the pads, do you re-apply heat after mounting on the horn to get a correct seat? "
I am a little unorthodox in some of my routines, perhaps because I am almost entirely self-taught - it happens in relatively remote places! I very rarely alter a pad in a key cup after installation.
I choose a pad of what I think is suitable thickness, considering the old pad before it was taken out, the thickness of both the felt and cardboard of the new pad, and the shape of the key cup hence how the pad sits in the key cup. I then install it with as much adhesive/filler as is needed to have the pad project from the key cup the right amount according to my educated guess and observations. I make sure the pad is installed EVENLY in the key cup. Then I install the key and evaluate. Almost always I use special tools I have made to tweak the alignment of the pad cup over the tone hole, until it the pad meets the tone hole 'perfectly'.... usually to a geometry that I think the manufacturer SHOULD have established had it in the first place! I never assume that the geometry of a key cup over a tone hole is made perfect and sacrosanct, because it seldom is!
This correction of alignment of key cups seems to be appropriate, because almost always, when I replace that pad again at a later date, any tweaking, if it is necessary at all, is very small.
Sometimes I realise I am too far out in my choice of pad, and so I put in a thicker or thinner pad before any tweaking of alignment.
Surprisingly often though, especially for the large keys, the manufacturer has made the key cup arm too long or short to get the key cup aligned correctly over the tone hole, even by juggling with pad thickness. In these situations, I usually resort to re-aligning the pad crooked in the key cup, while the key is mounted on the instrument, rather than modifying the length of the key cup arm, which would be the perfectionist fix more satisfying to me.
I see no excuse for this misalignment in these days of CNC machining. It is only a matter of feeding different figures into the machine's programming to move a tone hole slightly further round an instrument to match the geometry of the keys being used.
"...Wouldn't lacquer be better if only because you can SEE it if there is any smear around the working part of the pad? I have experienced clear glue in a not so positive way."
I think I represent most technicians in saying that we usually rely on testing with a feeler to ascertain the alignment of a pad over a tone hole, rather than by observing any oozed glue. Any excess of the glue-gun type of glue is trickier to remove, but if you catch it at the right temperature, just before it sets, you can quickly swipe it off with a No 14 (1.23 mm?) crochet hook traced around the edge of the key cup.
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Author: Gordon (NZ)
Date: 2005-11-21 03:51
Avie wrote:
".....except I cant get B & C in the upper Reg. over the break to play at all. As suggested It could be the pads not seating well enough on the related pad holes since there seems to be enough spring pressure now."
Getting F/C & E/B pads to seal together and reliably is by far the most demanding part of any clarinet adjustment (barring articulated G# mechanism)
EVERYTHING in the vicinity must be right:
- Posts secure.
- No significant play in the pivots.
- No binding in the pivots.
- Perfect alignment of pads with tone holes, using almost-zero finger pressure.
- No over-squishy materials in the crowsfoot linkage.
- When the E/B key is pressed, the underside of the key's 'touchpiece' should be in a plane parallel to that of the crowsfoot.
- No unwanted friction in the linkage to the left hand levers, or anywhere else. There are many possibilities here!
- Perfect adjustment of the crowsfoot linkage.
- The underside of the E/B key's "touchpiece" should be in in a plane parallel to the surface of the crowsfoot.
- No air pockets between the pads and the key cups.
- Level tone holes
etc, etc
Unless you have attended to ALL of these, then don't expect all-fingers B to sound easily, especially the left hand fingering.
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Author: Avie
Date: 2005-12-01 19:34
My Buffet is playing again. The pads are all seating fairly well and it plays at least as well as it did before the repad. There is still a hesitation in some runs going quickly from Ab to left hand little finger C (long arm key). It could be particially because of the long key arm pivot and/or me. The reason for the repad was to improve the C key action but to no avail but it was all worth the learning experience. The right hand little finger C (short arm key)is fine. I may have to compensate on this clarinet and live with the results. Thanks for all your technical help. Avie
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Author: Gordon (NZ)
Date: 2005-12-02 05:29
Avie, there are many possible reasons for the left fingering for C being hesitant, such as:
- imperfect closing of the pad on the tone hole. (the right hand fingering exerts more force, overcoming this.
- F/C lever spring binding against the key itself, or the timber.
- F/C lever pivot binding, or sloppy.
- Spring on F/C lever to thick for its length, which is common on Buffet.
- When the spring is mounted on the key, the tip of the spring is pushing up against a minute 'wall at the end of a groove it has worn in the timber or the post, whatever it rests against.
- Silencing material between the F/c lever and key is too thick, such that force is used up in crushing the material, rather than being transfered to closing the pad.- Too much friction in this silencing material.
- a slicing action at this linkage rather than a rolling action as with two gear teeth meshing. This occurs from poor design, which is almost the norm.
- Sloppy pivot on F/C key, such that pad alignment with the tone hole is different when using the lever, because it exerts an UPWARDS force on the key, whereas pressing the key exerts a downwards force on the key (against the pivot)
- The touch piece of the lever is too close to in line with the pivots, such that the finger exerts insufficient leverage.
etc.
The problem is likely to be several of such items, and I suspect that only the more astute technicians actually diagnose and deal with all these.
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Author: Avie
Date: 2005-12-02 22:45
I wonder if other clarinet players have trouble fingering from Ab to left hand C lever! Coincidently I have the same problem with my Selmer. Most other finger combinations respond well on both clarinets. Im confused! As mentioned. It may deserve the attention of a very astute technicion. Thanks Gordan...Avie
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