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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=BobDavis88@aol.com
href="mailto:BobDavis88@aol.com">BobDavis88@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> May 08, 2003 8:27 =
AM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Design of cutoff =
bar</DIV>
<DIV><BR></DIV>
<DIV><FONT face=arial,helvetica><FONT lang=0 face=Arial size=2 =
FAMILY="SANSSERIF">Many pianos with cutoff bars have an open space, =
or a
different species of [filler] wood outside the cutoff. Is there a way =
to gain
the acoustical advantage of a cutoff bar, but have it appear =
traditional on
the top side? For instance, could the ribs be notched and continued on =
to the
rim, just to support this area? I realize this is a waste of good =
spruce, but
it would not call attention to itself, and there are some situations =
in which
that is a good thing.</FONT></FONT></DIV></BLOCKQUOTE>
<DIV><FONT face=Arial size=2>Yes. In some cases we leave the =
soundboard
full-size and glue it down over the cutoff. We still terminate the ribs =
at the
cutoff and use short pseudo-ribs between the cutoff and the rim to =
support the
dead area of the soundboard. It is much more difficult to glue up this =
way and
we resist doing it unless the client is really insistent. Generally we =
glue up
in two stages. The soundboard board goes in first so we have ready =
access to the
cutoff for clamping. Then the filler goes in. Clamping is not a =
critical. We
always put something in there to keep acoustical energy from =
cross-coupling
around the edge of the cutoff.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<BLOCKQUOTE
style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; =
BORDER-LEFT: #000080 2px solid; MARGIN-RIGHT: 0px">
<DIV><FONT face=arial,helvetica><FONT lang=0 face=Arial size=2 =
FAMILY="SANSSERIF">Is the cutoff bar affixed to the beams? In one =
picture it
appears to pass over the metal termination plate for the beams. Is =
this a
problem?</FONT></FONT></DIV></BLOCKQUOTE>
<DIV><FONT face=arial,helvetica><FONT lang=0 face=Arial size=2
FAMILY="SANSSERIF">Yes. It is glued and doweled. In general we cut =
away for
clearance between the cutoff and any metal components (Usually =
incorrectly
called "tone-collectors") that may be down there. This includes any =
"Centripital
Tension Resonators" that may be in the way.</FONT></FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=arial,helvetica><FONT lang=0 face=Arial size=2
FAMILY="SANSSERIF"><FONT face="Lucida Sans"
color=#000080></FONT></FONT></FONT> </DIV>
<DIV><FONT face=arial,helvetica><FONT lang=0 face=Arial size=2
FAMILY="SANSSERIF"><FONT face="Lucida Sans" =
color=#000080></FONT> </DIV>
<DIV
style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; =
BORDER-LEFT: #000080 2px solid; MARGIN-RIGHT: 0px">It
appears to be the approximate cross section of a bridge. Am I seeing =
this
right?</DIV>
<DIV><FONT face="Lucida Sans" color=#000080></FONT> </DIV>
<DIV><FONT face="Lucida Sans" color=#000080>No. They are some larger =
that that.
I usually make them 50 to 60 mm wide and between 30 and 50 mm tall. They =
are
made of maple (usually).</FONT></DIV>
<DIV><FONT face="Lucida Sans" color=#000080></FONT> </DIV>
<DIV><FONT face="Lucida Sans" color=#000080>Del</FONT></DIV>
<DIV><FONT face="Lucida Sans" color=#000080></FONT> </DIV>
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