string breaking test

[Stéphane Collin]

Sorry Ric,

I was not clear at all.  Here is my second try :

The strings taken from the piano that was constructed in 1870, which strings
I beleave to be original, broke all at a tension around 1500 N/mm².
The strings made by Röslau, and bought by me in 2000 (the year 2k), broke
also at a tension around 1500 N/mm².
I concluded that I could use modern wire to restring the 1870 piano, but was
worried about the fact that my measures don't agree with the data given by
Stephen Paulello.  Here are those data :
"
Five kind of wire have been processes, to be adapted depending of the era of
the instruments and their scaling, though allowing for an optimum
solicitation of the material used.

M type : thickness 0,75 à 1,6 mm for instruments after 1930 ; specifically
it have a long and full medium body, with a very precise spectral
definition.

Type O : de 0,75 à 1,6 mm, for French pianos using originally Firmini
strings from 1880 to 1920 (depending of the scaling) . Breaking strain run
from 1800 to 2200 Newton au mm² depending of the gauge.

Type I : de 0,575 à 1,6 mm, pianos from 1840 to 1870 approx. (depending of
the scaling) . Breaking strain runs from 1400 à 1800 Newton au mm² depending
of the gauge.

Type II : de 0,525 à 1,4 mm, intended for forte-pianos from 1820 to 1840
approx. (depending of the scaling) Breaking strain run from 1000 à 1400
Newton / mm² depending of the gauge.

Type III : de 0,2 à 0,7 mm designed for forte-pianos, harpsichords, spinets
and clavichord, build before 1820 approx. (depending of the scaling).
Breaking strain run from de 800 à 1600 Newton /mm² depending of the gauge.

"

Mysteries keep confusing my poor mind.

Stéphane Collin.


----- Original Message ----- 
From: "Richard Brekne" <Richard.Brekne@grieg.uib.no>
To: "Pianotech" <pianotech@ptg.org>
Sent: Tuesday, March 02, 2004 8:51 PM
Subject: Re: string breaking test


>
> Perhaps I misunderstand... but it seems to me that 2000 N/mm^2 is
> exactly half way inbetween 1800 and 2200 N/mm^2.
>
> Whats the give then ?
>
> RicB
>