Author: Gordon (NZ)
Date: 2003-03-26 10:56
Binding refers to unacceptable, excessive friction.
In a pivot it can be caused by:
- A hinge (pivot) tube which the manufacture has never fitted correctly to the shaft that goes through it - common even with top makes.
- Grit, rust or residues from old glue between the tube and the shaft.
- Pivot tube is too long so that it jams between the supporting posts.
- A post is loose and has been rotated by the spring mounted in it.
- A bent tube or shaft.
- A pivot shaft where the axis of the thread at one end is at a slight angle to the axis of the rest of the shaft. Result - jamming only when the rod is tightened.
- A burr at the end of the pivot tube, either from wear or scruffy manufacture. (Similar result)
- for a pivot that involves point screws rather than a pivot tube, when the point screws screw up hard against the key.
- Bent point screw.
Excessive friction for a throat A key's spring can be caused by:
- The spring being a fraction of a millimetre too short.
- Th spring sliding (during operation) to a minute wall at the end of a groove it has worn in the timber.
- The timber here is lined with a minute piece of metal where the spring contacts. This can be mis-located, or installed on an 'uphill' slope for the spring to struggle against.
- The contact point of the spring needs lubrication but has none.
- The contact point of the spring is slightly rough, sharp, or rusty.
- The spring is bent incorrectly such that its EFFECTIVE length is too short.
Excessive friction can also be caused by a chunk of cork where the A/G# regulating screw touches the A key - a chunk that the screw has chewed a hole into.
Binding pivots can occur anywhere there is a pivot.
The throat A spring, because of its shortness, is the fussiest on the instrument.
The higher up the instrument that any leak is, the more notes it affects, especially those notes involving keys much further down the instrument.
So if there is a leak in the a key's pad it will barely affect A, but will dramatically affect notes that involve a lot more fingers.
There are far more parameters and possibilities involved with most aspects of clarinet servicing than most players ever realise. It is a rare amateur repairer who can get his own instrument even in mediocre order.
In summary, if even your teacher has a problem playing some notes, SEE A GOOD TECHNICIAN!! They know many times more about these things than players do. A good technician could find any problems in your instrument in a FRACTION of the time it took me to write this!
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