<!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 6.00.6000.16544" name=GENERATOR> <STYLE></STYLE> </HEAD> <BODY id=role_body style="FONT-SIZE: 10pt; COLOR: #000000; FONT-FAMILY: Arial" bottomMargin=7 bgColor=#ffffff leftMargin=7 topMargin=7 rightMargin=7> <DIV>Del, thanks for the reply.  My Knabe plate stress coupler is back in it's plate stress coupler position, awaiting stringing.  Appreciate your insight.</DIV> <DIV> </DIV> <DIV>Dave Smith</DIV> <DIV>SW FL</DIV> <DIV> </DIV> <BLOCKQUOTE dir=ltr style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 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=fandrich@pianobuilders.com href="mailto:fandrich@pianobuilders.com">Delwin D Fandrich</A> </DIV> <DIV style="FONT: 10pt arial"><B>To:</B> <A title=pianotech@ptg.org href="mailto:pianotech@ptg.org">'Pianotech List'</A> </DIV> <DIV style="FONT: 10pt arial"><B>Sent:</B> Monday, October 15, 2007 2:23 PM</DIV> <DIV style="FONT: 10pt arial"><B>Subject:</B> Plate stress couplers</DIV> <DIV><BR></DIV> <DIV dir=ltr align=left><FONT face="Comic Sans MS" color=#000080 size=3></FONT> </DIV><BR> <BLOCKQUOTE dir=ltr style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000080 2px solid; MARGIN-RIGHT: 0px"> <DIV class=OutlookMessageHeader lang=en-us dir=ltr align=left> <HR tabIndex=-1> <FONT face=Tahoma size=2><B>From:</B> <A href="mailto:pianotech-bounces@ptg.org">pianotech-bounces@ptg.org</A> [mailto:pianotech-bounces@ptg.org] <B>On Behalf Of </B>Dave Smith<BR><B>Sent:</B> October 13, 2007 7:31 PM<BR><B>To:</B> Pianotech List<BR><B>Subject:</B> Re: Mystery part<BR></FONT><BR></DIV> <DIV></DIV> <DIV><FONT face="Comic Sans MS" color=#000080 size=3></FONT> </DIV> <DIV>I almost hate to ask the question, but is this brace a good idea in the first place?  At least for someone who is just trying to restore at least as good as the original.  Not yet to the point of improving on piano design perfection!?!</DIV> <DIV><FONT face="Comic Sans MS" color=#000080 size=3></FONT> </DIV> <DIV>Dave Smith </DIV> <DIV>SW FL<SPAN class=140175416-15102007><FONT face="Comic Sans MS" color=#000080 size=3> </FONT></SPAN></DIV><SPAN class=140175416-15102007> <DIV> <HR> </DIV></BLOCKQUOTE> <DIV dir=ltr> </SPAN><SPAN class=140175416-15102007> </SPAN></DIV> <DIV dir=ltr><SPAN class=140175416-15102007><FONT face="Comic Sans MS" color=#000080 size=3>Well, although plates can obviously be designed to function quite well without them, they are not a bad idea. Often when these mechanisms are used the plates are also a bit lighter so it's a <EM>Really Good Idea</EM> to properly fit them and replace them during the final plate setting. This is not so much a worry about the middle of the tuning pin panel deflecting down as it is one of possibly overstressing the bass/tenor plate strut once string tension is applied. These mechanisms keep some of the bending stress off of the bass/tenor plate strut (generally a weak point in the casting). </FONT></SPAN></DIV> <DIV dir=ltr><SPAN class=140175416-15102007><FONT face="Comic Sans MS" color=#000080 size=3></FONT></SPAN> </DIV> <DIV dir=ltr><SPAN class=140175416-15102007><FONT face="Comic Sans MS" color=#000080 size=3>While better than nothing, the design found in your small Knabe is not the best I've seen. The horn and wedge system found in Steinway construction, for example, is a much better system. As is the system found in certain larger Knabe grands: </FONT></SPAN></DIV> <DIV dir=ltr><SPAN class=140175416-15102007><FONT face="Comic Sans MS" color=#000080 size=3></FONT></SPAN> </DIV> <DIV dir=ltr><SPAN class=140175416-15102007><FONT face="Comic Sans MS" color=#000080 size=3><IMG alt="" hspace=0 src="cid:001e01c80f82$c8b947d0$0201a8c0@self678d11cb63" align=absMiddle border=0></FONT></SPAN></DIV> <DIV dir=ltr><SPAN class=140175416-15102007><FONT face="Comic Sans MS" color=#000080 size=3></FONT></SPAN> </DIV> <DIV dir=ltr><SPAN class=140175416-15102007><FONT face="Comic Sans MS" color=#000080 size=3>This type has the advantage of being easily adjustable both during original construction as well as later during rebuilding.</FONT></SPAN></DIV> <DIV dir=ltr><SPAN class=140175416-15102007><FONT face="Comic Sans MS" color=#000080 size=3></FONT></SPAN> </DIV> <DIV dir=ltr><SPAN class=140175416-15102007><FONT face="Comic Sans MS" color=#000080 size=3><FONT face=Arial color=#000000 size=2>  <HR> </FONT> <DIV><SPAN class=140175416-15102007>[Quote] </SPAN></DIV> <DIV><FONT face=Arial size=2>Del, A manufacturer's rep once told us the plate stress coupler (a bolt in this case) served to enhance the tone by transferring vibrations from plate to belly rail.  Any truth to that? </FONT></DIV> <DIV><FONT lang=0 face=Arial size=2 PTSIZE="10" FAMILY="SANSSERIF">Bob Maret, RPT<BR>Piano Technician<BR> <HR> </FONT></DIV></FONT></SPAN></DIV> <DIV dir=ltr><SPAN class=140175416-15102007><FONT face="Comic Sans MS" color=#000080 size=3></FONT></SPAN> </DIV> <DIV dir=ltr><SPAN class=140175416-15102007><FONT face="Comic Sans MS" color=#000080 size=3>I'm not sure what advantage there would be to transferring vibrations from the plate to the bellyrail. Bellyrails are not generally designed to function well as energy transducers; i.e., soundboards. Their advantage is to structurally stabilize the plate and, if anything, prevent energy losses by helping to prevent spurious plate vibrations and resonances. </FONT></SPAN></DIV> <DIV dir=ltr><SPAN class=140175416-15102007><FONT face="Comic Sans MS" color=#000080 size=3></FONT></SPAN> </DIV> <DIV dir=ltr><SPAN class=140175416-15102007><FONT face="Comic Sans MS" color=#000080 size=3>As well, while the older Knabe plates I've encountered have generally still been quite massive, Steinway took the opportunity to significantly reduce the mass of their plates without any compromise in overall stability.</FONT></SPAN></DIV> <DIV dir=ltr><SPAN class=140175416-15102007><FONT face="Comic Sans MS" color=#000080 size=3></FONT></SPAN> </DIV> <DIV dir=ltr><SPAN class=140175416-15102007><FONT face="Comic Sans MS" color=#000080 size=3>Del</FONT></SPAN></DIV> <DIV dir=ltr><SPAN class=140175416-15102007> <P><FONT size=2>Delwin D Fandrich<BR>Piano Design & Manufacturing Consultant<BR>620 South Tower Avenue<BR>Centralia, Washington 98531  USA<BR>Phone  360.736-7563<BR><<A href="mailto:fandrich@pianobuilders.com">mailto:fandrich@pianobuilders.com</A>> </FONT></P></SPAN></DIV></BLOCKQUOTE></BODY></HTML>