soundboardinstal again

[Isaac sur Noos]

Ron,

Me think (may be wrongly) that on the opposite, the fact that a so
small dimension is involved show us the importance of a better joint
(last news from the day !)

The inserting under tension of the soundboard seem the only way to
have some tension in the panel, in the rib direction (across grain)
the modulus of elasticity is said to be 3 Kg cm2 vs. 100 Kg cm2 in
direction of grain.
So if we wish to have some tension in the panel that looks like a
convenient method, more than compression crowning.

Stephen have forced back some boards with shims on the straight side
with good results he say, when we see the dimensions involved, that
looks like a possibility.

The panel is said to be shaped with 1 cm more than the internal size
of the rim, was said. If possible a soundboard that should be pinched
in the rim should work better from an acoustical point of view (a very
good joke to future rebuilders !)

Idem on the belly rail, while some brands have stopped the insertion
there (Seiler for instance).
But I seem to understand that in the actual conception in the USA the
soundboard assembly is viewed as an auto supported device is not it ?

Greetings

Isaac OLEG

Entretien et reparation de pianos.

PianoTech
17 rue de Choisy
94400 VITRY sur SEINE
FRANCE
tel : 033 01 47 18 06 98
fax : 033 01 47 18 06 90
cell: 06 60 42 58 77

> -----Message d'origine-----
> De : pianotech-bounces@ptg.org
> [mailto:pianotech-bounces@ptg.org]De la
> part de Ron Nossaman
> Envoye : lundi 21 juillet 2003 02:12
> A : davidlovepianos@earthlink.net; Pianotech
> Objet : Re: soundboardinstal again
>
>
>
> >A point made earlier in this discussion about the
> tightness of fit around
> >the perimeter brings up a question.  I know that some
> soundboard installers
> >prefer to do the bridgework with the board out of the
> piano, i.e. notching
> >and pinning.  So, they lay in the board, and put the plate
> in on top, clamp
> >in a few key places, wedge the board down under the struts
> and set the
> >bearing, take everything out and notch and pin the bridge.
>
> Since I haven't built a power notcher like Del's, I prefer
> doing it on the
> bench, or screwed to a clamped down 1x10, without having to
> bend over a
> soundboard at all.
>
>
> >With a certain
> >amount of gap around the perimeter of the board, you would
> think that the
> >board would move outward slightly in the wedging process
> such that setting
> >the bearing would give a different result than when the
> board was actually
> >glued in.  Any comments on this method and whether it
> presents a problem?
> >
> >David Love
>
>
> One more time -----
> The difference in length measured from straight end to end
> of a 36" 60'
> crowned rib (crown height 0.225"), and that measured over
> the curve is
> under 0.004". If that will make the difference, we're all
> doomed and had
> just as well take on paper routes.
>
> Ron N
>
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