Math/Physics Problem: degrees of rotation of tuning pin =howmuchpitch change

[Richard Brekne]

I was going to mention something along these lines but had decided to 
not... but since you bring this in....

It is of course interesting to delve into as much as you can.  I have my 
own project going with explaining pitch changes due to string 
deflections at the bridge and and with the help of PhD Alexander Galembo 
arrived at a set of math formulas for calculating change in pitch for 
change in length. This employs Hookes law and is a different approach 
then using elongation formulas... which I have yet to see a sensible 
explanation for in this context.  Regardless of approach... one is 
immediately confronted with a host of friction moments and it gets very 
iffy for more then very general querries right away.

In the end... as related to the present issue... about all you can model 
with maths here is how much increase in tension a free standing string 
will experience for any given amount of movement for a pin of a given 
diameter. Once you start adding termination and other friction points as 
in a real piano you are not going to get much of anything meaningful 
with math models... only hints of what <<should be>> under uniform and 
ideal conditions... which of course never are in existence.

In the end... a techs job is from a practical perspective a matter of 
feeling, touch, listening... and putting these together to arrive at a 
sensation of <<knowing>> what the string and pin are doing for whatever 
kind of stress you are exerting on them. That takes experience... lots 
of it.  The rest is academic... interesting... perhaps useful.. perhaps 
as much a goose trail as anything else depending on the tech pursuing 
the trail.

Cheers
RicB


    Theory and Practice of Piano Tuning by Brian Capleton has a 40 page
    chapter on Setting the Pin.
    www.amarilli-books.co.uk

    Ed Sutton