[pianotech] String elongation/Fenner article

[David Ilvedson]

Has anyone found the second tension change on piano wire, i.e. pitch raise...2 passes has less of the drop is pitch % as the first?   

David Ilvedson, RPT
Pacifica, CA  94044

----- Original message ----------------------------------------
From: "Jim Busby" <jim_busby at byu.edu>
To: pianotech at ptg.org
Received: 7/31/2009 10:21:43 AM
Subject: Re: [pianotech] String elongation/Fenner article


>Albert,

>That was exactly my point, or the point I was trying to ask about with this article. 
>But if this has been discussed a dozen times on Pianotech I shouldn't have posted it 
>w/o looking back.

>While Fenner indeed talks about break % and the usual stuff, this notion of length 
>alone as "string elongation", aside from any tension issue in tuning stability, had me 
>wondering... I'm studying it on my own (well, with Vince Mrykalo) and think it is an 
>issue worth looking at.

>Jim Busby RPT

>From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf 
>Of Albert Lord
>Sent: Thursday, July 30, 2009 9:35 PM
>To: pianotech at ptg.org
>Subject: Re: [pianotech] String elongation/Fenner article


>On Thu, Jul 30, 2009 at 1:18 PM, Ron Nossaman 
><rnossaman at cox.net<mailto:rnossaman at cox.net>> wrote:
>    The greater the elongation under the tension necessary to produce the required 
>pitch, the higher the break%...

>I read Fenner to say that longer non-speaking
>string segments also increase elongation and
>stability as you implied:
>   the long front scale should mean that the overall string is longer, so the effect of a 
>given string length change (seasonal, from wood reaction to humidity) has a 
>relatively smaller affect on overall string tension, and the unisons should stay in tune 
>better.

>with no increase in breaking %age (speaking length
>and tension unchanged).  So elongation and breaking
>%age are not always linked.  Do I state this correctly?

>Albert