Klarinet Archive - Posting 000525.txt from 1997/10

From: Jrykorten@-----.com
Subj: RE: Manufacturing Tolerances
Date: Mon, 13 Oct 1997 10:10:03 -0400

Regarding Ed Lacy's comments on manufacturing tolerances:

<<
But, what material is being used. I don't even know what a "plethysmograph"
is,
>>

A spelling test! Actually a pressure sensing chamber - place a preemie on a
ventilator inside and monitor chest expansion/contraction in order to
determine pulmonary function non-invasively.

<<
but if it is made from a hard metal such as steel,
achieving a tolerance of .001" is a very different matter than getting the
same degree of accuracy in an object made of an organic material such as
wood.
>>

Acrylic which has more in common with wood than metal regarding dimensional
stability. (It must be annealed after gluing as well which also distorts
shape).

<<
As I have mentioned before, wood exhibits a "rebound effect" when
worked. Some of the fibres will be displaced rather than removed by the
tool, and then will have a tendency to try to return to their original
position and dimensions after the tool is removed.
>>

My position is that this does not necessarily have to be the case. If so they
are rushing the manufacturing process and we suffer. My model makers use wood
as modelling material when they design a mold. They certainly wouldn't use it
if they couldn't dimension it properly.

Really when you think about it, there is as much variability between
clarinets of the same manufacture as one would expect from different
manufacturers. I think that is inexcuseable when the sound of the instrument
(given the same player) should be determined by the nature of the geometry
(bore design, frasing) of the instrument.

Jerry Korten
NYC