<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html xmlns:v="urn:schemas-microsoft-com:vml" = xmlns:o="urn:schemas-microsoft-com:office:office" = xmlns:w="urn:schemas-microsoft-com:office:word" = xmlns:st1="urn:schemas-microsoft-com:office:smarttags" = xmlns="http://www.w3.org/TR/REC-html40"> <head> <META HTTP-EQUIV="Content-Type" CONTENT="text/html; = charset=iso-8859-1"> <meta name=ProgId content=Word.Document> <meta name=Generator content="Microsoft Word 10"> <meta name=Originator content="Microsoft Word 10"> <link rel=File-List href="cid:filelist.xml@01C53EE1.ED5F32D0"> <o:SmartTagType = namespaceuri="urn:schemas-microsoft-com:office:smarttags" name="PersonName"/>  <style>  </style>  </head> <body bgcolor=white lang=EN-US link=blue vlink=purple = style='tab-interval:.5in'> <div class=Section1> I’m not sure I understand the concept which means that it must not work, right<= span style='mso-char-type:symbol;mso-symbol-font-family:Wingdings'>J<= /span>? The RC&S = designers seem to be doing a pretty good job of control. That plus the installation of vertical hitches and an adjustable = plate mounting system allows a lot of fine tuning. Also, it seems to actually work, = whoa!<o:p></o:p> <o:p> </o:p> <div> David Love <st1:PersonName>davidlovepianos@comcast.net</st1:PersonNa= me> = <o:p></o:p> </div> -----Origi= nal Message----- From: = pianotech-bounces@ptg.org [mailto:pianotech-bounces@ptg.org] On Behalf Of Thomas Cole Sent: Monday, April 11, = 2005 9:53 PM To: Pianotech Subject: Re: Virtual = Ribs, A new crown support method <o:p> </o:p> Adjustability = comes to mind. You can come only so close to the optimum amount of stiffness in = the different areas of the board when choosing panel and rib materials and dimensions, and that stiffness may change as the panel ages. So magnets = would allow for a fine tuning, no? Tom Cole David Love wrote: <![if !supportLineBreakNewLine]> <![endif]><o:p></o:p> Why would this be better than simply creating a rib = crowned and supported panel that can be compressed to the requisite stiffness = through the use of downbearing without overstressing the = panel?<u7:p></u7:p><o:p></o:p> <u7:p> </u7:= p><o:p></o:p> <div> David Love <a = href="mailto:davidlovepianos@comcast.net">davidlovepianos@comcast.net</= a> <u7:p></u7:p><o:p></o:p> </div> -----Original Message----- From: <a href="mailto:pianotech-bounces@ptg.org">pianotech-bounces@ptg.org</a> = [<a href="mailto:pianotech-bounces@ptg.org">mailto:pianotech-bounces@ptg.or= g</a>] On Behalf Of <a href="mailto:Erwinspiano@aol.com">Erwinspiano@aol.com</a> Sent: Monday, April 11, = 2005 6:34 PM To: <a href="mailto:pianotech@ptg.org">pianotech@ptg.org</a> Subject: Re: Virtual = Ribs, A new crown support method<o:p></o:p> <u7:p> </u7:p><o:p></o:p></= p> <div> <div>   = RIc<u7:p></u7:p><o:p></o:p> </div> <div>   = May the force? be with you = brother.grin<u7:p></u7:p><o:p></o:p> </div> <div>   = Dale<u7:p></u7:p><o:p></o:p> </div> <blockquote style='border:none;border-left:solid windowtext = 1.5pt;padding:0in 0in 0in 4.0pt; margin-left:3.75pt;margin-top:5.0pt;margin-bottom:5.0pt;border-color:-moz= -use-text-color -moz-use-text-color -moz-use-text-color blue'> Hi = folks After a few months of experimenting, I am ready to announce a new (I = believe)  method of supporting crown for any type of soundboard. = The method allows for both restoring crown and supporting it in older panels, and designing new panels in which the concerns of mass levels = and degree of assembly stiffness can be to a far greater degree treated = independantly. In essence, an array of repelling high power neodym magnets of appropriate dimmensions and strengths are used to support crown against = downbearing from the strings. One set are imbeded in soundboard button = similar wooden sheaths and are attached to the soundboard with glue and = screws.  Opposing these is another set which are mounted into a = very strong wooden beam such that their distance from the soundboard attached = magnets can be adjusted easily from below.  One can either choose = to simply provide support directly under the bridge, or without too much = difficulty, contrive what amounts to a system of virtual ribs with fully = adjustable support for crown. For edification... Neodym magnets that measure 30 mm Ø by 5 mm thick = can hold / push approximately 25 kilos.  Since there is no phsyical = connection between the soundboard and opposing magnets, the assembly is = not directly mass loaded. Hence stiffness and crown support is provided = without mass loading. More later on as I formalize an article on a working example I am hoping = to finish soon. As is my habit... this is an open source idea, I encourage any and all = to take up and refine it in their own fashion.  My own initial = results indicate that the principle is very successful. Cheers Richard Brekne<u7:p></u7:p><o:p></o:p> </blockquote> </div> <div>  <u7:p></u7:p></= font><o:p></o:p> </div> </div> </body> </html>