string breaking test

[Stéphane Collin]

Hello Isaac



> The way the tension is applied, is the string pre tensioned first and
> leaved for some time before the test, and other parameters influence
> the test results more than a little, been said.
>
> That is why test are made more or less 10 times for each gauge to be
> relatively accurate (and evened).
> What counts more than the breaking strain is the limit of the elastic
> zone.

Indeed : my friend, who did the measures, told me that the way the string is
attached to the measuring machine was the most determinent factor in
reproductibility of the measures.  He ended up attaching the strings by
means of making a coil around a pin and fixing that pin in the machine.  But
then, his readings about elastic deformation were too unaccurate, as the
coil winding spoiled them.

> Nowadays I like
> their timber a lot.

I shall certainly give them a try.  Did I understand that it is Guillemenot
who sells those strings ?

> as the
> wire stiffen with time differently than Roslau

Do you mean they take more time to stretch out ?


> For the moment I like the warmness and the
> open power of those strings, they are pleasing to my ears, nowadays,
> the projection is different from Roslau, as the stiffness.

Do you mean they are more stiff ?  And the projection is greater ?  Does
more stiff material lead to more inharmonicity in the sound ?  And more
inharmonicity to better projection ?

As I explained in my reply to Philip, I feel confused (again) by the
discrepancies between theory and real world.  Do the formulas given by Dave
Roberts ("Calculating technician" articles from the late 70's) apply to wire
that breaks at an average 2000 N/mm² ?  Can I possibly have made 25%
relative error in measuring 1500 N/mm² breaking strength for modern Röslau
wire ?

Thanks

Stéphane Collin