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<DIV><FONT color=#000080>Dale,</FONT></DIV>
<DIV><FONT color=#000080></FONT> </DIV>
<DIV><FONT color=#000080>You are referring to an effect you notice at =
the point
of initially gluing the soundboard assembly to the rim. Certainly the =
soundboard
assembly is stiffening up. You are changing it from a free-floating =
panel to a
clamped-edge panel. Apples and pomegranates in the context of this =
discussion.
</FONT></DIV>
<DIV><FONT color=#000080></FONT> </DIV>
<DIV><FONT color=#000080>I (and, presumably, M&H) am referring to =
an effect
expected to last through the ages. I would respectfully suggest that you =
read up
on the phenomena of wood creep. Look specifically at wood deformation =
under load
over extended periods of time.</FONT></DIV>
<DIV><FONT color=#000080></FONT> </DIV>
<DIV><FONT 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 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> April 23, 2002 5:54 =
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: Soundboard =
Installation
& MC</DIV>
<DIV><BR></DIV><FONT face=arial,helvetica><FONT lang=0
face="Times New Roman Greek" color=#000040 size=3 =
FAMILY="SERIF"><I>In a
message dated 4/23/2002 9:08:29 AM Pacific Standard Time, <A
href="mailto:pianobuilders@olynet.com">pianobuilders@olynet.com</A>
writes:<BR><BR></FONT><FONT lang=0 style="BACKGROUND-COLOR: =
#ffffff"
face=Arial color=#000000 size=2 FAMILY="SANSSERIF"></I><BR>
<BLOCKQUOTE
style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #0000ff 2px =
solid; MARGIN-RIGHT: 0px"
TYPE="CITE">Subj:<B>Re: Soundboard Installation & MC
</B><BR>Date:4/23/2002 9:08:29 AM Pacific Standard Time<BR>From:<A
=
href="mailto:pianobuilders@olynet.com">pianobuilders@olynet.com</A></FO=
NT><FONT
lang=0 style="BACKGROUND-COLOR: #ffffff" face=Arial =
color=#000040 size=2
FAMILY="SANSSERIF"><BR>Reply-to:<A
href="mailto:pianotech@ptg.org">pianotech@ptg.org</A></FONT><FONT =
lang=0
style="BACKGROUND-COLOR: #ffffff" face=Arial color=#000040 =
size=2
FAMILY="SANSSERIF"><BR>To:<A
href="mailto:pianotech@ptg.org">pianotech@ptg.org</A></FONT><FONT =
lang=0
style="BACKGROUND-COLOR: #ffffff" face=Arial color=#000040 =
size=2
FAMILY="SANSSERIF"><BR><I>Sent from the Internet
</I><BR><BR><BR><BR><BR>----- Original Message -----<BR>From: =
"Farrell"
<mfarrel2@tampabay.rr.com><BR>To: =
<pianotech@ptg.org><BR>Sent:
April 23, 2002 4:12 AM<BR>Subject: Re: Soundboard Installation & =
M
=
<BR><BR>  =
;
Del, Ron,Terry<BR>
=
<BR> &nb=
sp;
I Read each of your post and I think I have a diiferent or =
additional
point of view about the comments about the rim having =
having no
effect on holding crown. The rim in my view at least is a supporting =
agent
to crown.<BR> Let me explain. Although from what my =
colleagues
Ron /Del have stated about emc at the time of ribbing and to the =
precrowning
of ribs and such I can say our methods are similar except for the =
redesign
factor.<BR> This to say were all building a pretty =
stiff
soundboard system. When I'm setting my bridge height for bearing I =
do this
as a dry fit with clamps and screws and such. With the plate =
installed over
the board and screwed and fastened down I then prestress the board =
with
wedges before cutting down the tops of the bridge to the height I =
want. Thus
setting my bearing.<BR> Once I,m happy with that I =
remove every
thing and finish the bridge, glue it on the board and glue it in the =
piano
somewhere between 6 to 7% emc or so.<BR>In spite of the board being =
very
stiff I find that it is much more easly forced down during my =
bearing
pre-stressing procedure and it demonstrates much more flacidity( is =
that a
word?) than after it is glued to the rim.<BR> With the =
rib
ends and board perimeter at last are glued to the rim the =
board takes
on an dramatic increased dimension of stiffness. </FONT><FONT =
lang=0
style="BACKGROUND-COLOR: #ffffff" face=Arial color=#000040 =
size=2
FAMILY="SANSSERIF"></BLOCKQUOTE><BR><BR></FONT><FONT lang=0
style="BACKGROUND-COLOR: #ffffff" face="Times New Roman Greek" =
color=#000040
size=3 FAMILY="SERIF"><I> </FONT><FONT lang=0
style="BACKGROUND-COLOR: #ffffff" face=Arial color=#000040 =
size=2
FAMILY="SANSSERIF"></I>So I will humbly disagree that the rim is not =
a
supporting agent of the crown for without it the strings would squash =
more of
the crown out as the rib ends and board edge are moving outward and =
lifting.
Without the Rim the rib ends and board edge would still =
woggle
around and lift when depressed in the middle.<BR> The other =
isuue is
that although the bearing is essentially a downward force it does push =
out
wards and into the rim at least a bit once the board IS glued in. =
Since we
have an arched system, vaguely similarto the concept of a flying =
buttress used
in cathedral construction,it is a resistive element.<BR>How much is I =
think
part of the debate here. <BR> I'm not saying the rim =
does
alot to hold a crown from diminishing I'm just saying it's a =
supporting
agent which aids the boards stiffness.<BR>>>>>>...Just =
my two
cents worth--------Dale
=
Erwin>>>>>>>>>><BR> =
</FONT><FONT lang=0 style="BACKGROUND-COLOR: #ffffff" face=Arial =
color=#000040
size=2 FAMILY="SANSSERIF"><BR><BR></FONT><FONT lang=0
style="BACKGROUND-COLOR: #ffffff" face=Arial color=#000040 =
size=2
FAMILY="SANSSERIF"><BR>
<BLOCKQUOTE
style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #0000ff 2px =
solid; MARGIN-RIGHT: 0px"
TYPE="CITE">Tery wrote<BR>> What argument would there be for =
drying prior
to installation?<BR>Del wrote<BR>With a compression-crowned board? =
It is
easier to work with and glue into<BR>the rim if it is dry, having =
little
crown.<BR><BR>With a rib-crowned board there is just the matter of
consistency. You don't<BR>want the board too dry or too wet--both =
have a
negative affect on the glue<BR>bonding strength. We rib our boards =
at 6.5%
and glue them in at 6.5% to<BR>7.5%.<BR><BR><BR>>Terry<BR>> =
Has this
become the "standard" because the "masters" did it that way =
back<BR>when it
was a fact that the rim supported the crown?<BR>Del<BR>It has never =
been a
'fact' that the piano rim supports the crown though many<BR>have =
believed
this over the years. Some argument can be made that beveling<BR>the =
rim--as
is the practice of some--does have some nominal effect =
on<BR>soundboard
crown, but it is very short-lived. Consider that this effect =
is<BR>greatest
in the treble region of the soundboard panel and yet this is =
the<BR>region
that typically looses its crown--certainly the stiffness related
to<BR>crown--the earliest in a compression-crowned soundboard =
system.
Obviously,<BR>the effect is minimal.<BR><BR><BR>>Terry<BR>> I =
suppose
if you flat ribbed it and dried the bajeezers out of it, the =
rim<BR>just
might help to hold a bit of crown - at least until it got off
the<BR>showroom floor!<BR><BR>If the rim actually did support crown =
you'd
never see a M&H with a flat<BR>board!<BR><BR>Wood--primarily the =
spruce
used in the soundboard system--simply has too<BR>much compliance and =
is to
susceptible to long-term creep for the rim to have<BR>any real =
function in
sustaining crown.<BR><BR>Del<BR><BR></BLOCKQUOTE><BR></FONT><FONT =
lang=0
style="BACKGROUND-COLOR: #ffffff" face="Times New Roman Greek" =
color=#000040
size=3 =
FAMILY="SERIF"><I><BR></BLOCKQUOTE></I></FONT></FONT></BODY></HTML>