 The Clarinet BBoard
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Author: Bill
Date: 2001-05-29 21:39
I recently posted a question under the topic subject "Repair Tech Question". I learned a lot about assembly, and bridge key linkage adjustment from the replies. Even though my horn is indeed out of adjustment, I did not realize that I was assembling the upper and lower joints of my horn(s) incorrectly.
Usually I aligned the upper and lower joint rings, and then gave the joints a little twist so my left pinky could comfortably reach the left hand little finger (pinky) keys. WRONG: My basic clarinet book says to put the two joints together so that the linkage mechanism is lined up. If this is not done correctly, the upper joint Eb/Bb key may not close completely when the lower joint Bb/F key is closed, or the upper key may be closed and the lower key open. You can check the simultaneous closure of the two keys with a feeler guage made from cigarette paper or a phone book page. John Butler also suggested playing Eb using the 1 - 4 fingering.
Incorrect bridge key linkage alignment can cause some notes to sound poorly, and/or the Bb/F key action to function poorly.
I found that different makers have different bridge key linkages, and you need to need to know what correct alignment looks like for your horn. Some horns allow a wider range of variation than others.
See the above mentioned topic for more information, and thanks again to those who helped me understand this topic.
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Author: Ken Shaw
Date: 2001-05-29 22:36
Bill -
Most instruments made today (particularly those made for beginners) have tapered edges and guides for the bridge key that avoid damage even with careless assembly.
Still, I use the way I was taught as a beginner.
1. Put some cork grease on the tenon on the bottom of the upper joint.
2. Cradle the upper joint in the palm of your left hand and your middle finger on its ring, which raises the bridge connector.
3. Hold the lower joint without touching the rings, so that the lower bridge connector doesn't raise. To do this, cradle your right hand under the lower end of the lower joint, with your fingers away from any keys or rods, or pressing on one or more of the 4 bottom pad cups. If your hands are large, you may have to lay your right thumb along the side of your index finger to avoid touching any keys or rods.
4. Put the joints together with a gentle rotating motion, and out of alignment, with the upper bridge connector turned clockwise (looking from the top) so that it doesn't touch the lower bridge connector.
5. Then be sure your left middle finger is on the ring, and gently twist the joints untill the bridge mechanism is aligned. If this is hard to do, you skipped step 1.
This is foolproof and works on everything except the Vitos with the alignment pin. For those, assemble the joints as far as you can while out of alignment, twist them into alignment and push them the rest of the way together.
Never rock the tenon into the socket, even on a plastic instrument. This puts excess wear on the cork and gets you into a bad habit for when you get a wood instrument, where it can crack the very thin area between the bottom of the lower joint socket and the hole beneath the pad connected to the rings.
Best regards.
Ken Shaw
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Author: Bill
Date: 2001-05-29 22:53
Ken: excellent. Beyond this how does one know/verify that the bridge is indeed aligned/assembled correctly? Maybe beginners clarinets are more forgiving than intermediate and professional horns. Also, the bridge key could be bent, and how could the beginner verify this? This is the point I was trying to make, maybe poorly.
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Author: Hiroshi
Date: 2001-05-30 05:02
>My basic clarinet book says to put the two joints together so that the linkage mechanism is lined up.
This is wrong. The brigde keys need not be lined up. If you request good technicians to adjust upper pads to allow your own alingnment, they will do that.
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Author: Bill
Date: 2001-05-30 09:23
But, then you have to make sure you adjust it to your alignment which is the "new" correct alignment.
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Author: Gordon (NZ)
Date: 2001-05-30 14:37
Consider the contacting faces of the bridge keys, i.e. either side of the linkage cork. Almost every clarinet is made so that these faces are tangential to the body (at that location on the body) when the keys are OPEN. However the only time that reliable linkage is required is when the keys are closed. If the geometry is such that contacting faces are tangential when the keys are closed, then slight variations in bridge key alignment (i.e. joint rotation) would have only minor significance. However with the way that clarinets ARE designed the alignment can be very critical indeed.
Ideally, when the keys are CLOSED the contacting face of the lower key should be cylindrical, concentric with the body, and the upper key should be flat (mainly so the cork glue is under less stress) and tangential, or cylindrical to match the lower key. Then the player could rotate the joint without upsetting the linkage at all. Furthermore, if designed like this then when the keys are open the angle of the face of the lower key is such that the joints can still safely be assembled with the usual twist without having to close the upper key as Ken does (unnecessarily for almost all instruments).
I can think of only two reasons for the geometry of this linkage on almost all clarinets being as it is:
1. The manufacturer INTENDED the player to have to adjust the linkage by turning the joint.
2. There mechanical thinking in the industry is so limited that this issue has not been seriously considered.
Would any manufacturer care to comment???
On most instruments I work on I alter this geometry to a more reliable state. With well seated pads, secure pivots, and 0.4 mm agglommerated cork/neoprene (for chip & tear resistance in case of mishandling, and dimensional stability) as linkage 'cork' this bridge mechanism is extremely stable and reliable.
There are also other areas of clarinet mechanism design which exhibit apparently little thought in many models, especially where excessive friction is introduced in springs and linkages.
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Author: Don Berger
Date: 2001-05-30 18:40
This is an excellent discussion of the "mechanics" of the clarinet, which IMHO need all of the "engineering" possible to produce the best playability. Nearly all of our good "technicians" doing pad/cork/key work will consider if the bridge halves have been bent side-to-side and adjust, as well as "radially" to give proper "long" [1-4] Eb/Bb AND Bb/F fingerings. Yes, there are other keyings that take some consideration to adapt the clar to the player and [for me] make life more pleasant. I do this on my horns and, after discussion, on student to "advanced" student insts. , which I believe a should be a [required?] repair function. Don
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