stretching wire

[Paul Chick]

Wouldn't the tuning pin fill with additional wire?
Paul C

Subject: Re: stretching wire

OK,

I think my intuitive mind wants me to think that as the tension on the wire 
increases, that the wire has to stretch.  On cogitating for a full second, 
it would make sense that that cannot be the case (at least there cannot be 
any appreciable stretch), otherwise, we would not be able to raise the pitch

on a given string.  If it stretched, the pitch would drop.

Completely understand the idea of bends.

Thanks,
William R. Monroe

>> Wouldn't the string have to stretch in order to be deflected?
>
> Of course, but not permanently, unless you put so much pressure on it that

> you damage it. Otherwise it springs back.
>
>
>>Does the string have to stretch to be tuned?  Are you simply saying that 
>>once tensioned and in a static state, the string does not passively 
>>stretch, but rather the bends around it's bearing points continue to 
>>change?  If we add more tension to it, or deflect it with the pizza wheel,

>>then it will stretch, up to it's elastic limit, yes?  If no, what accounts

>>for string deflection?
>>
>> Thanks,
>> William R. Monroe
>
> There is no appreciable (nothing is absolute, but it's inconsequential) 
> long term stretch, or creep, of piano wire below it's yield point tension 
> and under around 600°F. So "pre-stretching" doesn't pre-stretch. It will 
> naturally immediately stretch under tension within it's elastic limits, 
> but long term pitch drop doesn't come from elongating wire. If the strings

> aren't forcefully bent around the bearing points, they will slowly do so 
> on their own under string tension and play, dropping in pitch as the 
> wire's path between bearing points straightens. Remember that, while the 
> straight string segments are (hopefully) well below their yield point 
> tensions, the bends at the bearing points have been forced beyond the 
> wire's yield point in order to make the bend.
> Ron N
>
>