Klarinet Archive - Posting 000381.txt from 1995/02
From: CLARK FOBES <reedman@-----.COM>
Subj: Mouthpiece changes
Date: Mon, 20 Feb 1995 18:08:04 -0500
Dan Leeson asked me to make a posting about his mouthpiece and what I
did to correct the problem.
Dan expressed to me that he was having difficulties producing his usual
sound and felt that either his instrument or mouthpiece had degraded. I
work on Dan's bass clarinet about every 3 to 6 months and know that his
horn is in good shape. I asked a few more questions and suggested the
possibility that his mouthpieces had changed.
I measured the mouthpiece and found that the table was slightly convex
(shaped like the outside curve of a sphere) rather than flat or slightly
concave. This test is fairly easy if you have a glass guage and the
standard set of feeler guages that are used to measure mouthpieces.
While holding the mouthpiece in your left hand place the glas guage on
the mouthpiece table and press the glass with your left thumb just below
the window. The glass should feel secure. Try wiggling the end of the
glass with your right hand. The glass should remain stable with a gentle
but firm pressure from the left thumb. If the glass moves easily the
mouthpiece table is most likely convex.
A more precise test is to place the mouthpiece in your left hand and
place the glass as before. Using the finest feeler guage (.0015) measure
the length of the curve. When the feeler is snug, roll your left thumb
toward you. If the table is warped the glass will lift slightly and the
guage will travel further. Some mouthpieces also are so badly humped
that the glass will also roll from side to side.
Many, many mouthpieces that I have measured over the past ten years
exhibit a slight convexity. I am not certain in those cases if it was
done intentionally or the maker intended the table to be flat and did
not quite achieve the ideal. It is very difficult to make a mouthpiece
truly flat by hand. Everett Matsen is one of the few who I have seen do
this with a high degree of success.
I like to leave a very slight concavity in the table of my mouthpieces.
This insures that the reed is sitting square (provided the reed is also
flat) and allows for some swelling of the reed.
There is a relatively easy fix for convex mouthpiece tables provided
that the problem is not too pronounced. But let me make a statement
and disclaimer first.
My #1 axiom of mouthpiece refacing is:
Don't work on the mouthpiece you are playing on unless you have
a really good back up that you would be willing to go
to.
My #2 axiom:
Once you work on a mouthpiece it will never be the same
That said let me make one other point. IF your mouthpiece plays fine
DON'T FIX IT!!!!! There are a lot of anomolies in mouthpiece making and
very often it may be the anomoly that makes your particular mouthpiece
fit you.
OK, you have read all this, you still think your mouthpiece is warped
and you want to correct it.
Cut a strip of #600 sandpaper approximately 1" wide and 6" long. Wrap
the strip around a smooth metal cylinder that is approximately .5" in
diameter. With the cylinder perpendicular to the mouthpiece, work the
area of the table just behind the window down to a point about .5" from
the end of the mouthpiece table. Use a smooth longitudinal stroke. I
take about 2 dozen light swipes and then check the table with my guage.
Be sure to wipe any rubber dust off the mouthpiece and the glass. If the
glass does not sit square repeat the process. You may have to rotate the
sand paper to insure that it is cutting. After you have reached the
point where the glass is sitting flat polish the worked area with 0000
steel wool.
Now, the glass may be sitting flat, but the length of the curve may have
also changed. As I said this is a simple quick fix and may not
necessarily give the desired results.
Clark W Fobes
