Wire stretching

[Jon Page]

Even after a single wire is replaced and the natural curves reduced and the 
wire 'rubbed'
the tension will go down in the following weeks. Not as much as had not the 
aforementioned
procedures been executed, they are just aspects of the event.

And if wire does not stretch, then why would some tuners pre-stretch wire 
for replacement?
To reduce the effects of that aspect of string replacement.

If wire does not stretch then why is the wrap on a bass string longer when 
the string is pulled up to pitch?

Seems to me that anything under tension _has_to give, even if 
minutely.  It's like RonN said a few
months ago . . . the fly did have an affect on the aircraft carrier; it's 
just that the result of the impact
was more readily visible on the fly than the ship.

I'm not saying that it continually stretches, it reaches a point where it's 
strength resists this and becomes stable.
Does it get drawn, over time, to the point of losing it's elasticity and 
that would account for new wire sounding better?

Obviously, I don't have answers; just unfounded theories allocated over the 
years.

Just trying to figure out fact from fiction/fantasy.

Jon Page


At 06:32 PM 4/5/2002 -0500, you wrote:
>    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???