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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=mkurta@adelphia.net =
href="mailto:mkurta@adelphia.net">Mike Kurta</A>
</DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A =
title=pianotech@ptg.org
href="mailto:pianotech@ptg.org">PTG List</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Sunday, May 25, 2003 6:49 =
AM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Bass bridge =
puzzler</DIV>
<DIV><BR></DIV>
<DIV><FONT face=Arial size=2> Hi =
Gang:</FONT></DIV>
<DIV><FONT face=Arial size=2> Two weeks ago, I =
duplicated a
bridge for a local tech from a 10 year old Baldwin console which =
had
split in the usual manner. After installation and attempting to =
pull the
bass strings up to pitch, the new bridge split again down the pin line =
on the
speaking length side of the bridge. Will now have to make =
another, but
don't want to have the same result. </FONT></DIV>
<DIV><FONT face=Arial size=2> A few =
points: Hard rock
maple was used, the dimensions, pin size and positioning were all =
closely
duplicated, and finished with DAG along the top. Grain =
orientation was
followed according to PTG information. The new bridge =
failed the
same way as the original one. We did not measure downbearing, =
felt there
was no need. </FONT></DIV>
<DIV><FONT face=Arial size=2> We are looking at =
some
possibilities: 1. I used the entire length of the new pin =
into the
wood, did it weaken the bridge along its length? Did the =
pins drive
in too tightly starting the split? Was there a flaw in the =
wood? I havn't seen it yet, so will examine. Should I use =
smaller
diameter pins next time? Should they be angled more toward the =
center
(each other) at the bottom of the bridge? Was there a design =
flaw in the
original bridge we are repeating? </FONT></DIV>
<DIV><FONT face=Arial size=2> Any ideas? =
HELP !
</FONT></DIV>
<DIV><FONT face=Arial size=2> Mike =
Kurta</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>Maybe the wood wasn't cured. I had one =
duplicated by
Schaff that split despite all my precautions. I =
suppose it's
possible that bridge pins driven in too hard might help it =
split. I've
had even soft pine split when driving in nails, even when I =
pre-drilled a hole
for the nail. This happens more often at the end of a board than =
in the
middle. Maybe if both the sides and the end were clamped somehow =
while
driving pins . . . or use one drill size larger?</FONT></DIV>
<DIV> --David Nereson, =
RPT</DIV></BLOCKQUOTE></BODY></HTML>