string breaking test

[Stéphane Collin]

Hello all.

I just made some strings breaking tests, and am a bit in trouble.
Have that beautiful Bechstein model IV in mint condition, from 1870, with I
believe original strings on it.
Asked a friend (engineer) to do the breaking tests on that wire, and at the
same time, do the same tests on modern wire.  Both tests led to this numbers
:  1870 wire breaks at about 1500 N/mm² and modern (2000) wire (Röslau) :
exactly the same.
Good news : I can restring that 1870 piano with modern wire.
Bad news : when I read Stephen Paulello papers, the numbers don't match at
all : he says modern wire should break at something between 1800 and 2200
N/m².
Any comments ?

Stéphane Collin