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<DIV dir=ltr align=left><FONT face="Comic Sans MS" color=#000080 =
size=3><SPAN
class=343060314-23062005>Dale,</SPAN></FONT></DIV>
<DIV dir=ltr align=left><FONT face="Comic Sans MS" color=#000080 =
size=3><SPAN
class=343060314-23062005></SPAN></FONT> </DIV>
<DIV dir=ltr align=left><FONT face="Comic Sans MS" color=#000080 =
size=3><SPAN
class=343060314-23062005>This is true only if the soundboard assembly =
is
compression-crowned where the thickness of the board is necessary to =
support
crown over the years. It's why diaphragmed soundboards collapse more =
rapidly
than do thicker boards.</SPAN></FONT></DIV>
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size=3><SPAN
class=343060314-23062005></SPAN></FONT> </DIV>
<DIV dir=ltr align=left><FONT face="Comic Sans MS" color=#000080 =
size=3><SPAN
class=343060314-23062005>If the soundboard is crowned using curved =
ribs the bulk
of the crown support comes from the rib and the panel functions more as =
a
non-structural diaphragm. In this system the thickness of the soundboard =
is
chosen based more on acoustical needs and less on structural =
requirements and 8
mm is quite adequate. This is especially true if a reasonable cutoff bar =
and a
fish are used.</SPAN></FONT></DIV>
<DIV dir=ltr align=left><FONT face="Comic Sans MS" color=#000080 =
size=3><SPAN
class=343060314-23062005></SPAN></FONT> </DIV>
<DIV dir=ltr align=left><FONT face="Comic Sans MS" color=#000080 =
size=3><SPAN
class=343060314-23062005>Del</SPAN></FONT></DIV><FONT face="Comic =
Sans MS"
color=#000080 size=3></FONT><FONT face="Comic Sans MS" =
color=#000080
size=3></FONT><BR>
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<FONT face=Tahoma size=2><B>From:</B> pianotech-bounces@ptg.org
[mailto:pianotech-bounces@ptg.org] <B>On Behalf Of
</B>Erwinspiano@aol.com<BR><B>Sent:</B> June 20, 2005 10:32 =
PM<BR><B>To:</B>
pianotech@ptg.org<BR><B>Subject:</B> Re: Rib Crowned Hamburgs
?<BR></FONT><BR></DIV>
<DIV></DIV><FONT id=role_document face=Arial color=#000000 =
size=2>
<DIV>
<DIV> Ron</DIV>
<DIV> 8 mm /.320ish is on the thin side for a 9ft =
grand
of any make . A board this thin doesn't really need much =
thinning. In
fact it's probably not thick enough in the treble. I'm unaware of =
the
German factory's rhetoric on panel thinning. I'm guessing it sounded a =
bit
thin? grin</DIV>
<DIV> Regards</DIV>
<DIV> Dale</DIV>
<BLOCKQUOTE
style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px =
solid"><FONT
style="BACKGROUND-COLOR: transparent" face=Arial color=#000000 =
size=2>Very
often the factory line doesn't match the actual product. How =
<BR>often have
we heard about the tapering of sound board panels from <BR>S&S. =
They may
have done it at some time but . . . The original board <BR>which I =
pulled
from a 1962 Hamburg D last year had a 8 mm thick panel =
<BR>everywhere. I
still have the original panel at the workshop.<BR><BR>Ron
O.</FONT></BLOCKQUOTE></DIV>
<DIV></DIV>
<DIV><FONT face="Comic Sans MS" color=#000080 =
size=3></FONT> </DIV>
<DIV> </DIV>
<DIV><FONT lang=0 face=Arial size=2 PTSIZE="10" =
FAMILY="SANSSERIF">Erwins
Pianos Restorations <BR>4721 Parker Rd.<BR>Modesto, Ca
95357<BR>209-577-8397<BR>Rebuilt Steinway , Mason &Hamlin
=
Sales<BR>www.Erwinspiano.com</FONT></DIV></BLOCKQUOTE></FONT></BODY></HTM=
L>