Maximum tension

[Richard Moody]

You can change the guage to lower the breaking point.  The thinner the wire,
the less tension needed to pull it to the desired pitch.   The fact that
strings break *around* the same pitch for all sizes (at the same length) is
for curiosity rather then design. Besides design should be based around
elasticity limits, not breaking points.  If length alone dictated scale,
considering spinets and concert grands, one or the other could not exist.
(although for both spinets and concert grands the highest notes have roughly
the same length for a while, so Newton's observations apply there) But for
the notes you mention, measure the length and guage, compute the tension,
then  choose the guage that gives the  tension at least a semitone below the
elasticity limit. Make that two semitones  + since there are reports of
pianos changing a semitone through humidy  alone.  Now if they keep breaking
at the upper bearing, and the tension is under 200 #  then you might have
too sharp of a bearing point.  Still though the elasticity limit of the core
wire should be known.  Were these aluminum wrapped in that Everett?   ---ric

----- Original Message -----
From: Paul <tunenbww@clear.lakes.com>
To: <pianotech@ptg.org>
Sent: Saturday, June 03, 2000 7:47 AM
Subject: Re: Maximum tension


> Nweton
> Would this explain why, for no apparent reason, strings in a section of a
> well known piano i.e. Everett studio has strings breaking in the bicord
> section during tuning and playing? Several tuners had a crack at this
piano
> and, finally the dealer replaced it with another one and no more problems.
> But I've often wondered if increased string length due to poor bridge
> placement was the problem.
>
> Paul Chick
>
> Newton wrote:
> > The point of this is that if the speaking length is too long
> > for a given pitch  changing the wire size will not change at
> > which pitch the string breaks.
> >
> >  It was discovered that the bridges were located too far from
> > the capo bar so the tension was way past safe breaking %.
> > Changing string sizes would not have solved this problem
> > either.  The manufacturer had to change the design.
> >