warning: intense discussion of tension

[Tom Sivak]

Ron
   
  Right, of course, it's not a linear measurement, but it is a measurement between two points, and I guess my question was "What two points?"  
   
  Seems to me, if you are correct, that references to plate tension increases due to pitch raises, etc., are really just guesses, and are not backed up by any scientific measuring of tension at all.  Which is kind of what it seemed like to me.
   
  One of the reasons I brought this up was to question, to myself, whether the only manipulation of the tuning pin that changed the tension on the plate was actually turning it.  (I imagined that any rendering of the string, via flagpoling, for instance, would not change the actual tension on the plate, since the overall tension of the string would not be changed.)
   
  Tom Sivak
  Chicago
   
  
Ron Nossaman <rnossaman at cox.net> wrote:
  
> I have read posts quoting the amount of tension on a grand plate, how 
> much tension is added with a pitch raise, references to low tension 
> scales, high tension scales...etc.
> 
> How is this measured? And where are the measuring points? I mean, are 
> we talking from one end of the plate down at the heel of the piano all 
> the way to the part that abuts the stretcher? Or from agraffe to hitch 
> pin? Tuning pin to hitch pin?
> 
> How about string tension? Does this refer solely to the speaking length 
> of the string, or from tuning pin to hitch pin? 
> 
> All these numbers get thrown around but in the end I have no 
> understanding of exactly what is measured, and how.
> 
> Does anybody know?
> 
> Just curious,
> 
> Tom Sivak
> Chicago

Hi Tom,
First off, tension isn't a linear measurement. A string at "X" 
tension can be of nearly any length that's likely to fit into 
a piano. Tension is nominally the same through the full length 
of the string, from hitch to tuning pin, and at any 
arbitrarily defined segment between the two points. The total 
tension, and tension changes resulting from a pitch change, as 
discussed on list, aren't directly measured, but rather 
calculated from the string scale and starting pitch. It's a 
means of getting a feel for something not easily measured 
directly.
Ron N

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