<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD><TITLE>Re: Rib grain orientation</TITLE>
<META http-equiv=Content-Type content="text/html; =
charset=iso-8859-1">
<STYLE type=text/css>BLOCKQUOTE {
PADDING-BOTTOM: 0px; PADDING-TOP: 0px
}
DL {
PADDING-BOTTOM: 0px; PADDING-TOP: 0px
}
UL {
PADDING-BOTTOM: 0px; PADDING-TOP: 0px
}
OL {
PADDING-BOTTOM: 0px; PADDING-TOP: 0px
}
LI {
PADDING-BOTTOM: 0px; PADDING-TOP: 0px
}
</STYLE>
<META content="MSHTML 5.50.4134.600" name=GENERATOR></HEAD>
<BODY bgColor=#ffffff>
<DIV><FONT face="Comic Sans MS" color=#000080></FONT> </DIV>
<BLOCKQUOTE dir=ltr
style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; =
BORDER-LEFT: #000080 2px solid; MARGIN-RIGHT: 0px">
<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: =
black"><B>From:</B>
<A title=sec@overspianos.com.au =
href="mailto:sec@overspianos.com.au">Ron
Overs</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> December 07, 2002 5:57 =
AM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: Rib grain =
orientation</DIV>
<DIV><BR></DIV>
<DIV>Hi all,</DIV>
<DIV><BR></DIV>
<DIV>I have been wondering about the merit<FONT color=#0000ff> (one =
which
seems to be a long standing tradition)</FONT> in orienting the rib =
grain such
that the growth rings run vertically, to set the medullary rays =
parallel to
the sound board panel.</DIV>
<DIV><BR></DIV>
<DIV>Now I can understand the logic behind this with the CC guys, =
since they
are likely to achieve a higher crown when the panel re-hydrates. =
However, in
the case of rib crowned construction, wouldn't it be advantageous to =
set the
grain in the rib such that the growth rings are horizontal and the =
medullary
rays perpendicular to the sound board panel? I am contemplating =
setting the
rib grain this way for piano no. 004<FONT color=#0000ff> (both 004 =
and 005 are
now sold before completion, which is quite a relief)</FONT>.</DIV>
<DIV><BR></DIV>
<DIV>Dale, Del and Ron N., and any others who may be using RC =
construction.
What are your thoughts on this matter?</DIV></BLOCKQUOTE>
<DIV dir=ltr><FONT face="Comic Sans MS" color=#000080>Since we're =
using nothing
by laminated ribs these days it hardly matters. But ... I did some =
experiments
much like those Ron N wrote about with similar results. At least in the =
sizes
and using the cross-sectional areas typical to soundboard ribs it really =
doesn't
seem to matter which way you align the grain.</FONT></DIV>
<DIV dir=ltr><FONT face="Comic Sans MS" =
color=#000080></FONT> </DIV>
<BLOCKQUOTE dir=ltr
style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; =
BORDER-LEFT: #000080 2px solid; MARGIN-RIGHT: 0px">
<DIV><FONT face="Comic Sans MS" color=#000080></FONT><FONT
face="Comic Sans MS" color=#000080></FONT><FONT face="Comic Sans =
MS"
color=#000080></FONT><BR></DIV>
<DIV>By the way, we decided to build the cut-off as a laminated =
curve<FONT
color=#0000ff> (I can't remember if I've mentioned this previously =
on the
list, since I had originally planned to make it from scarfed =
material)</FONT>.
We increased the cut-off rail section size to 50 mm wide by 35 mm =
deep, using
17 laminates of 2.9 mm thickness. I will try bending it with 4 mm =
laminates
for piano 006. When cutting and drum sanding the laminates at 3 mm it =
is quite
wasteful of wood. I'll get some photos of the buck and cut-off scanned =
and
onto the website soon.</DIV></BLOCKQUOTE>
<DIV dir=ltr><FONT face="Comic Sans MS" color=#000080>Within =
reason it doesn't
matter how thick you make the laminates. Thicker laminates are =
physically harder
to bend but, unless you try to vacuum-bag the things, any press you =
come up
with will undoubtedly be able to handle whatever you throw in there. You =
will
also get more spring-back with thicker veneers but if you were to use, =
say, 5
laminates each 10 mm thick I doubt you'd have enough spring back to =
worry about.
Thinner laminates are easier to bend and will give less springback =
but are
more awkward to work with, require more adhesive and will require a much =
longer
period of time to completely dry and stabilize. </FONT></DIV>
<DIV dir=ltr><FONT face="Comic Sans MS" =
color=#000080></FONT> </DIV>
<DIV dir=ltr><FONT face="Comic Sans MS" color=#000080>As with most =
everything
else in the piano it's a compromise.</FONT></DIV>
<DIV dir=ltr><FONT face="Comic Sans MS" =
color=#000080></FONT> </DIV>
<DIV dir=ltr><FONT face="Comic Sans MS" =
color=#000080>Del</FONT></DIV>
<BLOCKQUOTE dir=ltr
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><FONT face="Comic Sans =
MS"
color=#000080></FONT><FONT face="Comic Sans MS" =
color=#000080></FONT><FONT
face="Comic Sans MS" color=#000080></FONT>
<DIV><BR></DIV>
<DIV>Ron O.</DIV><X-SIGSEP><PRE>--
</PRE></X-SIGSEP>
<DIV>_______________________<BR><BR>OVERS PIANOS - SYDNEY<BR>Grand =
Piano
Manufacturers</DIV>
<DIV><FONT face="Comic Sans MS" color=#000080></FONT><FONT
face="Comic Sans MS" color=#000080></FONT><BR></DIV>
<DIV>Web: http://overspianos.com.au</DIV>
<DIV>mailto:info@overspianos.com.au</DIV>
<DIV>_______________________</DIV></BLOCKQUOTE></BODY></HTML>