Wire stretching

[A440A@aol.com]

 jon writes:

>I didn't respond beyond my initial statement of wire stretching, wire 
>easing through the friction
>at bearing points, plate compression and case deformation because of the
>
>intensity of a zealous tirade
>but would like to hear opinions on the matter.

Richard adds:

>>I would be curious to know what they think happens that more or less
>>corresponds to what we ignorant remaining humans think is string stretching 
?

   I find it interesting that a new piano takes a year for the wire to 
"stretch",  but a single replacement string stabilizes completely in one 
month.   Once the wire has had all the stresses relieved, starting from the 
hitch pin onward with constant tension maintained (as all the bends get a 
small thunk from a brass rod and hammer) I don't see them continually 
stretching.  I see mature pianos that go up and down the same amount between 
summer and winter,  but it is very close to the same.  
   Carbon steel doesn't fatigue  unless you get close or surpass its elastic 
limits, no matter how many cycles,  (think old valve springs in understressed 
motors,  they will last forever).  Once the outer radii of all the bends has 
been settled, (I see it as becoming neutralized as a source of directional, 
restorative force to the string), I don't see much drop in pitch. So, I don't 
really think the steel is continually stretching, like glass does in old 
windows, (it puddles up at the bottom). 
     I think that the soundboard's slow descent is responsible for the 
majority of late-life pitch loss, and its much more immediate collapse that 
takes place during the first year or so under compression gives the 
impression that all that wire is "stretching".   How come I find clear 
unisons that are 15 cents below where I left them on new pianos?  It would be 
pretty coincidental for all those wires to stretch the exact same amount, no? 
 
   I don't KNOW what that wire is doing without an electron microscope, so I 
can't state it as fact, but I think the pitch loss is more dependant on the 
elasticity of the wooden sounding structure than the wire.    
Regards, 
Ed Foote RPT 
  Maybe I can figure out how to relate this to temperaments, huh???