[CAUT] pre-stretching new string?

[A440A at aol.com]

Fred writes: 
<< Could be "not
significant in 99% of all applications, but there's enough creep to cause
100 cents of pitch drop in piano strings over the course of a year, and
another 100 cents over the next 20."  >>

Greetings, 
    The majority of the flattening of a new string is in the 
COIL!!!!!!!!!!!!!!!!
There is usually about 150 cents worth of slack in a three turn coil around 
the tuning pin.  If anybody doesn't believe this, simply put on a new string, 
tighten it up to a semitone sharp and then, with a small pair of vise-grips, 
make sure the becket is smashed in tight.  Then, grab the coil with the grips, 
(set them just short of locking so you get maximum compression on the coil), 
and begin twisting in the direction of the string.  You will hear the pitch 
plummet.  I routinely do this on string repairs and after a follow-up of 10 or so 
cents a week later, the strings stay put.   
    Theoretically, the becket will never see the tension of the speaking 
length because of the friction taken around the pin, but if you stroke the coil in 
this fashion, you will move a tremendous amount of slack into the top string.
   On bass strings, it is well known that squeezing the hitch pin loops will 
cause the string to drop, but if you will grab the barrel,(the tightly wound 
finale of the hitch pin loop), and give it a gentle back and forth twist, (not 
a rotational twist but, rather, side to side), you will hear anywhere from 10 
to 20 cents drop.   
   Ron is right, carbon steel reacts to stress almost instantly. The bends 
around the bridge pins will take a while for the plastic deformation that occurs 
on the outside circumference of the bend to allow the further deformation 
through the diameter of the wire, but that is still neglible compared to getting 
the slack out of the coil. 



Ed Foote RPT 
http://www.uk-piano.org/edfoote/index.html
www.uk-piano.org/edfoote/well_tempered_piano.html
 <BR><BR><BR>**************************************<BR> See what's free at 
http://www.aol.com.</HTML>