A string's treatment/ Isaac

[Isaac OLEG]

Joe, Ron,

I am also saying to my friend that to apply with consistence this
treatment one may compute the scale to know where is that limit. I was
answered that we generally stay within the dangerous zone, as the
plastic deformation occur in the plastic zone limit that is beginning
(slowly) at 40% solicitation, and the original 80 %of breaking strain
zone (which is the real plastic deformation of a string) is lessened
25% (the breaking strain given by the wire maker is lessened 25% for
all computation because of the deformation problems we meet when the
string is put in the piano).

Then the rule I was given was to stay within 70 % solicitation, but
not less than 60 % - (that is why I suspect your computation to use
the "real" in theory breaking strain.


When I first read that description (in a document coming from a
seminar my friend have done) I had the same reaction that you, that is
B.S.) but then I remember how difficult we work to stabilize the
tunings during the first year(s) , and the change in tone that occur
at the same time. Any method that allow that to be done in the shop is
good in my opinion.

Nowadays it is easy to check the process on a few strings after a
stringing, and we can see then what the result is, if bad no problem
to change a few strings more is not it ?

The scaling spreadsheet ask for an initial pitch to compute the
tensions, they do not at this date compute taking in account the way
we really tune the pianos (meaning the reference pitch of C8 may well
be 450 Hz if we go that way)

Indeed that is a small grand Schimmel, they have been building them
with too long treble strings, and the tone is not that good there (and
they are prone to break strings also) I agree with you on that one.


The tension of this C88 string with 0.775 mm string was computed  83
Kp (another scaling give me 786 N and 89% solicitation
for C7 I find on my spreadsheet  75% solicitation - 743 N still high.

I have not other views on Shimmers scales for larger models, just
remember that they use that long treble strings in most. I will check
that with some friends, make up my mind on it, before saying that the
man is full of something.

On your personal comment, no need to be so exited !

Now where would be the difference before having the definitive plastic
deformation of the string occurring in 5 years or in a few days ? do
you consider that strings are "old" after 5 years use/tuning ? , on
the contrary, they seem to tone very well at that time, and the
stability is hopefully attained then.

No need to explain that to the customer, do you explain him that you
are lacquering the hammers ? I guess no, any time I talk about lacquer
to a pianist he is believing this is a trick as the ones used by
automotive dealers to have you believe the gearbox is good ! (and
indeed that looks like it)

I hope some will test that (me ?) - the strings are not supposed to
break more after that treatment, in fact they are said to be breaking
because of the too many tunings they need (and because of the pianists
of course).

Well that's another view on the subject.

Greetings .

Summer is hot there

Isaac OLEG



Isaac OLEG

Entretien et réparation de pianos.

PianoTech
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> -----Message d'origine-----
> De : pianotech-bounces@ptg.org
> [mailto:pianotech-bounces@ptg.org]De la
> part de Joseph Garrett
> Envoyé : vendredi 11 juillet 2003 03:56
> À : pianotech@ptg.org
> Objet : Re: A string's treatment/ Isaac
>
>
> Isaac,
> You said: "BTW, Joe, we checked the scaling of a little
> grand Shimmel, with
> 55 mm
> at c8 and 93% of breaking strain (at 442 pitch) this is
> not really a
> low tension scale, other octaves give us values between 75 and 85%
> breaking strain. where do that appreciation comes from ?
> (other models
> may be ?)"
> First: What the heck is with the "442"? Second: I don't
> know what kind of
> scale program you are using, in relation to formulae, but
> the numbers you
> posted, IF they were correct, (which I believe they are
> NOT.), would be a
> disaster waiting, (a short time), to happen. The common
> rule that I was
> taught, (by Del), was not to exceed 55% - 60% of the
> breaking strength,
> EVER!,unless it is impossible to avoid!!  Any scale that I
> have done on
> Schimmels have always been in the low 170's, (plain wire),
> which is, by
> todays scaling standards, a low tension scale. Most of
> these were 5'6" or
> larger, however. So, if you are checking a Short PSO MADE
> by Schimmel, then
> all bets are off. Most PSO, ie small, ie "infantile" grands
> are scaled off
> the map, with the idea that they need to SCREAM, in order
> to be any good!
> <G> Stupid thinking, as most "infantile" grands are used in
> small rooms that
> don't need "power", IMO. However, even that is stupid, as
> higher tension
> scales do not necessarily create "power". (Just bad sound
> and Harmonic
> imbalance, IMO.)
> On the original subject: having read you further postings,
> I have come to
> the conclusion that someone is yanking your leg....OR is
> just plain full of
> it. In order to do what you say is needed on these "new"
> strings, you would
> have to, first, do a complete scale evaluation of the
> piano. Then you would
> have to calculate for each note what the "elastic" point,
> that you are
> aiming at, is. Then you would have to tune the piano with
> this information
> as a criteria, which would sound like so much crap. AND
> you'd have to
> convince the client that this is what the client has to
> endure to establish
> a "great/stable" sound. Humph! All tripe, (or other organic
> substances),
> IMO!!!!
>
> Joe Garrett, RPT, (Oregon)
>
> Been There, Didn't Like It, So I'm Here To Stay! [G}
>
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