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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=Erwinspiano@aol.com
href="mailto:Erwinspiano@aol.com">Erwinspiano@aol.com</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A =
title=pianotech@ptg.org
href="mailto:pianotech@ptg.org">pianotech@ptg.org</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> November 23, 2002 10:14 =
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: Belly rail crown - =
Why???</DIV>
<DIV><BR></DIV>
<DIV><FONT face=arial,helvetica><FONT lang=0 face="Times New =
Roman" size=2
FAMILY="SERIF">In a message dated 11/23/2002 10:00:34 AM Pacific =
Standard
Time, <A =
href="mailto:pianobuilders@olynet.com">pianobuilders@olynet.com</A>
writes:<BR></FONT><FONT lang=0 style="BACKGROUND-COLOR: #ffffff"
face="Times New Roman" color=#000000 size=3 =
FAMILY="SERIF"><BR></FONT><FONT
lang=0 style="BACKGROUND-COLOR: #ffffff" face="Times New Roman" =
color=#000000
size=3 FAMILY="SERIF">Del<BR>....Recognizing that by in large most =
on the list
are building rib crowned boards that retain more of there crown when =
under
load than the former compression stlye boards. Rib crowned boards =
being much
stiffer by design, thanks to higher rib radii and stiffer spruce =
rib
material (formerly sugar pine) and deeper ribs....
</FONT></FONT></DIV></BLOCKQUOTE>
<DIV><FONT face=arial,helvetica><FONT lang=0 =
style="BACKGROUND-COLOR: #ffffff"
face="Times New Roman" color=#000000 size=3 FAMILY="SERIF"><FONT =
face="Comic Sans MS" color=#000080>They don't necessarily start out =
that way.
While the rib-crowned soundboard certainly has the potential of greater
stiffness -- there is always the option of more and taller ribs -- in =
practice
I'm not sure they start out all that much different. A well done
compression-crowned soundboard can be quite stiff indeed. But it may not =
keep
that stiffness very long. It's in holding the long term stiffness that =
the
rib-crowned soundboard comes out ahead. </FONT></FONT></FONT></DIV>
<DIV><FONT face=arial,helvetica><FONT lang=0 =
style="BACKGROUND-COLOR: #ffffff"
face="Times New Roman" color=#000000 size=3 FAMILY="SERIF"><FONT =
face="Comic Sans MS" color=#000080></FONT> </DIV>
<BLOCKQUOTE
style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; =
BORDER-LEFT: #000080 2px solid; MARGIN-RIGHT: 0px">
<DIV> I see nothing wrong with the beveled rim =
personally,
if my boards are retaining a good amount crown even when strung I see =
no
reason to induce another unnecessary possible strain at the edge of =
the board
by changing all the beveled rastens that come through the shop to a =
flat edge.
No, I'm not saying you were advocating that either.</DIV></BLOCKQUOTE>
<DIV><FONT face="Comic Sans MS" color=#000080>Well, I don't know =
that there is
all that much wrong with the practice. I'm mostly just not convinced it =
does
much good. </FONT></DIV>
<DIV><FONT face="Comic Sans MS" color=#000080></FONT> </DIV>
<BLOCKQUOTE
style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; =
BORDER-LEFT: #000080 2px solid; MARGIN-RIGHT: 0px"><FONT
face="Comic Sans MS" color=#000080></FONT>
<DIV> Simply clamping a piece of spruce to a bench =
and
bending it isn't exactly like the continuos rim of board being glued =
to a
curving rim. Gluing the board to the rim gives the whole structure a =
cohesive
stiffness it doesn't have before that. </DIV></BLOCKQUOTE>
<DIV><FONT face="Comic Sans MS" color=#000080>Come on, Dale, you =
know better
than that. Sure, gluing the board to the rim makes it act like a =
clamped-edge
diaphragm, but wood is still awfully thin wood and it still bends under =
load.
Especially so when the load is essentially across-grain and most of it =
is along
the bent side or at roughly a 45º angle as most of it =
is along
the bellyrail and the straight side. And along the bass curve, well, who =
cares?</FONT></DIV>
<DIV><FONT face="Comic Sans MS" color=#000080></FONT> </DIV>
<BLOCKQUOTE
style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; =
BORDER-LEFT: #000080 2px solid; MARGIN-RIGHT: 0px">
<DIV> Also the board is often thinned down to as little as =
.250 at
the edges so undue stress once again not desired. The 1 and 1/2 =
degerees
typically found in the rim joint could as practicallity or compromise =
be
reduced to half that and this angle would more likely conform to the =
residual
crown angle after stringing.</DIV></BLOCKQUOTE>
<DIV><FONT face="Comic Sans MS" color=#000080>And, that's pretty =
much my
point. </FONT></DIV>
<DIV><FONT face="Comic Sans MS" =
color=#000080></FONT> </DIV><FONT
face="Comic Sans MS" color=#000080></FONT>
<BLOCKQUOTE
style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; =
BORDER-LEFT: #000080 2px solid; MARGIN-RIGHT: 0px"><FONT
face="Comic Sans MS" color=#000080></FONT>
<DIV> Perhaps petty, lame and faulty thinking but =
it's mine
all mine.</DIV></BLOCKQUOTE>
<DIV><FONT face="Comic Sans MS" color=#000080>Yup. Lame it is. And =
you can have
it. Unless it's already there in which case I'll have some =
too.</FONT></DIV>
<DIV><FONT face="Comic Sans MS" color=#000080></FONT> </DIV>
<DIV><FONT face="Comic Sans MS"
color=#000080>Del</FONT></DIV></FONT></FONT></BODY></HTML>