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<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: =
black"><B>From:</B>
<A title=Richard.Brekne@grieg.uib.no
href="mailto:Richard.Brekne@grieg.uib.no">Richard Brekne</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A =
title=pianotech@ptg.org
href="mailto:pianotech@ptg.org">Pianotech</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> August 18, 2003 10:38 =
AM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: More on soundboard =
crown</DIV>
<DIV><BR></DIV><FONT face="Comic Sans MS" color=#000080></FONT>
<P><BR>Now correct me if I am wrong.. but I understand this to mean =
that a CC
board will be stiffer, both unstrung... and increasingly so when =
downbearing
is applied. Assuming that is correct, </P></BLOCKQUOTE>
<P dir=ltr><FONT face="Comic Sans MS" color=#000080>Which it is =
not.</FONT></P>
<P dir=ltr><FONT face="Comic Sans MS" =
color=#000080></FONT> </P>
<BLOCKQUOTE dir=ltr
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BORDER-LEFT: #000080 2px solid; MARGIN-RIGHT: 0px">
<P>and putting aside all other compression damage discussion for a =
second or
two... I have a question about this long term so called compression =
set.
</P></BLOCKQUOTE>
<P dir=ltr><FONT face="Comic Sans MS" color=#000080>By this are =
you implying you
don't believe the phenomena exists? Check The Wood Handbook (USDA) and
Understanding Wood (R. Bruce Hoadley).</FONT></P>
<P dir=ltr><FONT face="Comic Sans MS" =
color=#000080></FONT> </P>
<BLOCKQUOTE dir=ltr
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BORDER-LEFT: #000080 2px solid; MARGIN-RIGHT: 0px">
<P>Given the absolute ideal climatic conditions over many years... =
would a
soundboard subjected to uniform compression set take on a permanent =
stiffness
as a result of that, or is it exactly the woods resistance to being =
compressed
that causes the stiffness ? Seems to me I also read something in one =
of Johns
posts that hinted in this direction. That a CC board <<properly
treated>> will eventually be pressed into a very stiff and =
permanent
condition. </P></BLOCKQUOTE>
<P dir=ltr>No. Compression set continues until some neutrality is =
reached. I.e.,
the point at which there is so little compression left within the panel =
that in
practical terms the wood fibers no longer deform. At this point =
compression and
crown and stiffness will be at their minimum point. </P>
<P dir=ltr> </P>
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style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; =
BORDER-LEFT: #000080 2px solid; MARGIN-RIGHT: 0px">
<P>On the side of this... and please forgive whatever lack of =
knowledge I
display in the asking, if compression from ribs being glued =
cross grain
to the panel is such a problem...even in RB boards.. is there no way =
of
contriving a rib such that it is a bit less constraining ? =
</P></BLOCKQUOTE>
<P dir=ltr><FONT face="Comic Sans MS" color=#000080>I don't =
understand any part
of this paragraph:</FONT><FONT face="Comic Sans MS"
color=#000080><BR> -- </FONT><FONT face="Comic =
Sans MS"
color=#000080>What compression from the ribs? In a compression-crowned =
soundboard system the compression is in the soundboard panel, not the =
ribs. The
rib-crowned system uses an entirely different technology that has been =
described
in infinite detail numerous times in print and on this
list.<BR> -- Compression from ribs is not a
problem.</FONT><FONT face="Comic Sans MS" =
color=#000080><BR>
-- Ribs, in a rib-crowned system, can be contrived to do just about =
anything you
want them to do.<BR> -- What do you mean by "less
constraining?"</FONT></P>
<P dir=ltr><FONT face="Comic Sans MS" =
color=#000080>Del</FONT></P></BODY></HTML>