<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=Content-Type content="text/html; =
charset=iso-8859-1">
<META content="MSHTML 5.50.4134.600" name=GENERATOR>
<STYLE></STYLE>
</HEAD>
<BODY bgColor=#ffffff>
<DIV><FONT color=#000080></FONT> </DIV>
<BLOCKQUOTE
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=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> October 16, 2002 6:04 =
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: Bridge cap =
materials</DIV>
<DIV><BR></DIV><FONT face=arial,helvetica><FONT lang=0 =
face="Times New Roman"
size=2 FAMILY="SERIF">In a message d</FONT><FONT lang=0
style="BACKGROUND-COLOR: #ffffff" face="Times New Roman" =
color=#000000 size=3
FAMILY="SERIF"><STRONG>ated 10/16/2002 2:10:47 PM Pacific Daylight =
Time,
</STRONG><A
=
href="mailto:mfarrel2@tampabay.rr.com"><STRONG>mfarrel2@tampabay.rr.com=
</STRONG></A><STRONG>
writes:<BR><BR></STRONG></FONT><FONT lang=0 =
style="BACKGROUND-COLOR: #ffffff"
face=Arial color=#000000 size=3 FAMILY="SANSSERIF"><BR>
<BLOCKQUOTE
style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #0000ff 2px =
solid; MARGIN-RIGHT: 0px"
TYPE="CITE"><STRONG>Subj:Re: Bridge cap materials =
<BR>Date:10/16/2002
2:10:47 PM Pacific Daylight Time<BR>From:</STRONG><A
=
href="mailto:mfarrel2@tampabay.rr.com"><STRONG>mfarrel2@tampabay.rr.com=
</STRONG></A><BR><STRONG>Reply-to:</STRONG><A
=
href="mailto:pianotech@ptg.org"><STRONG>pianotech@ptg.org</STRONG></A><=
BR><STRONG>To:</STRONG><A
=
href="mailto:pianotech@ptg.org"><STRONG>pianotech@ptg.org</STRONG></A><=
BR><STRONG><I>Sent
from the Internet
=
</I><BR><BR> &=
nbsp;
Terry</STRONG></BLOCKQUOTE>
<DIV><BR><BR></FONT><FONT lang=0 style="BACKGROUND-COLOR: #ffffff" =
face="Times New Roman" color=#000000 size=3
=
FAMILY="SERIF"><STRONG> =
=
I did a test this afternoon as I was working on a bridge. I took a =
piece of
maple with 27 grains an inch and one that had 6. I drilled a whole in =
each for
a no. 8 bridge pin. It took about twice the force of the hammer to =
drive the
pin in the tight grain piece. I then drove each pin back and forth =
twice and
the tight grain piece stayed much tighter than the other. <BR> =
As Ron
said the other day if you use the wider grain stuff it compresses =
more, and
drilling a smaller hole will obviously be =
required.</STRONG></FONT></DIV>
<DIV><FONT face="Times New Roman"></FONT> </DIV></BLOCKQUOTE>
<DIV><FONT face="Lucida Sans" color=#000080>A petty point, perhaps, =
but the
<EM>amount </EM>of compression--i.e., the physical displacement of the =
wood
cells--is the same in both types of wood. As long as the hole diameter =
and the
size of the pin remains the same the amount of compression would =
also be
the same if you used spruce or balsa. The resistance to that =
compression,
however, is a whole other matter. The tight-grain maple resists =
compression much
more than does balsa--or the earlywood of loose-grain maple. Hence the =
lower
force required to drive the pin into the loose-grain maple--there is =
much more
earlywood in there. Also, there is less long-term compression set in the =
latewood of any species than there is in the earlywood. </FONT></DIV>
<DIV><FONT face="Lucida Sans" color=#000080></FONT> </DIV>
<DIV><FONT face="Lucida Sans" color=#000080>The reason horizontally =
laminated
maple or birch stock works so well in this application is that the =
common
adhesive used--usually based on resorcinol resins but it's true to some =
degree
with other adhesives as well--tends to penetrate and stiffen the =
wood
fibers adjacent to the glue line making them even more resistant to =
compression
and to compression set. This is especially true when high temperatures =
and
pressures are used to lay up the laminate.</FONT></DIV>
<DIV><FONT face="Lucida Sans" color=#000080></FONT> </DIV>
<DIV><FONT face="Lucida Sans" color=#000080>Del</FONT></DIV>
<BLOCKQUOTE
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> </DIV></BLOCKQUOTE></FONT></BODY></HTML>