<HTML><FONT FACE=arial,helvetica><FONT COLOR="#000040" SIZE=3 FAMILY="SERIF" FACE="Times New Roman Greek" LANG="0"><I>In a message dated 5/4/2002 8:22:43 AM Pacific Standard Time, Richard.Brekne@grieg.uib.no writes:<BR>
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<BLOCKQUOTE TYPE=CITE style="BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px">Subj:<B>Re: Curve on Bridge Bottom </B><BR>
Date:5/4/2002 8:22:43 AM Pacific Standard Time<BR>
From:<A HREF="mailto:Richard.Brekne@grieg.uib.no">Richard.Brekne@grieg.uib.no</A></FONT><FONT COLOR="#000040" style="BACKGROUND-COLOR: #ffffff" SIZE=2 FAMILY="SANSSERIF" FACE="Arial" LANG="0"><BR>
Reply-to:<A HREF="mailto:pianotech@ptg.org">pianotech@ptg.org</A></FONT><FONT COLOR="#000040" style="BACKGROUND-COLOR: #ffffff" SIZE=2 FAMILY="SANSSERIF" FACE="Arial" LANG="0"><BR>
To:<A HREF="mailto:pianotech@ptg.org">pianotech@ptg.org</A></FONT><FONT COLOR="#000040" style="BACKGROUND-COLOR: #ffffff" SIZE=2 FAMILY="SANSSERIF" FACE="Arial" LANG="0"><BR>
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Farrell wrote:<BR>
The only bridge I had laying around was from an upright and it was notched at the tenor/treble break, so I followed your suggestion over the 39" tenor segment - it bowed 5/16" with 100 lbs applied in the middle (my son stood on it).<BR>
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> I'm not sure what I was supposed to observe. Kinda seemed to act like a big rib.<BR>
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> Richard wrote<BR>
Thinking from a "every little bit does some good" perspective one would easily buy into the idea that a crowned bridge would contribute to the soundboard crown at least to some degree. And 100 lbs is a nice big round figure.... half a<BR>
mans weight and well so at that. You might take one of those pre-crowned ribs... one of the long ones and see how much it takes to press it flat as well for comparision.....<BR>
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</FONT><FONT COLOR="#000040" style="BACKGROUND-COLOR: #ffffff" SIZE=2 FAMILY="SANSSERIF" FACE="Arial" LANG="0"> Richard, Terry<BR>
It doesn't take much to flatten an unsupported rib as it doesn't really take on its maximum stiffness till after it becomes part of the ply wood componet comprising the whole soundboard system at which point the cumulative resistive forces of cross banded woods and compression takes effect. I agree with Ron that the bridge because of its shape simply rotates as the board flattens but there is still some nominal resistance to bearing. Every little bit does some good. 100 lbs is a 100 lbs which IF that is what it is, is roughly the same reisistance as one rib</FONT><FONT COLOR="#000040" style="BACKGROUND-COLOR: #ffffff" SIZE=2 FAMILY="SANSSERIF" FACE="Arial" LANG="0"><BR>
</FONT><FONT COLOR="#000040" style="BACKGROUND-COLOR: #ffffff" SIZE=2 FAMILY="SANSSERIF" FACE="Arial" LANG="0"><BLOCKQUOTE TYPE=CITE style="BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px"><BR>
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.>>>>>>>Best>.................Dale Erwin</BLOCKQUOTE><BR>
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