[CAUT] pre-stretching new string?

[Michael Jorgensen]

   Ed is right on how important settling coil, hitch pin etc. is. If I am
tuning for a concert 9 AM and a treble string breaks, I replace and tune to
about 5 beats per second sharp.   After five minutes, it's down to correct.
After that, it drops in a sort of "half life".  If tuned after about 1/2
hour one bps sharp, it is less than 2 bps flat six hours later, sometimes
still right on.   In  late afternoon I go home and don't want to come back,
I tune it as far sharp as I can stand.  The next day, I check and have never
found it more than a small amount flat, 1 bps at worst, sometimes right on,
or even slightly sharp. Three of my four concert instruments are string
breakers.  I suppose I should restring them, but they're getting restrung a
note at a time.  
    I am very careful to do all Ed states.
-Mike Jorgensen   


On 6/5/07 9:41 PM, "A440A at aol.com" <A440A at aol.com> wrote:

> 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
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