<HTML>In a message dated 4/26/2002 12:18:51 PM Pacific Standard Time, RNossaman@KSCABLE.com writes: <BLOCKQUOTE TYPE=CITE style="BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px">Subj:Re: Soundboard Installation & MC Date:4/26/2002 12:18:51 PM Pacific Standard Time From:<A HREF="mailto:RNossaman@KSCABLE.com">RNossaman@KSCABLE.com</A> Reply-to:<A HREF="mailto:pianotech@ptg.org">pianotech@ptg.org</A> To:<A HREF="mailto:pianotech@ptg.org">pianotech@ptg.org</A> Sent from the Internet >  Hi Ron </BLOCKQUOTE>          Hey somedays I can't string two cohesive thoughts together. I know what I'm talking about but I'll be darned if anybody else can figure it out. <BLOCKQUOTE TYPE=CITE style="BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px">.                Dale wrote > >>>>>>>>Well almost. Is it your opinion that none of the downbearing load is > transfered down our gloriously precrowned rib./board stucture? or is it just > an almost  negligable  consideration because of the absorption of bearing > force from  the panel itself? One thing I didn't say was how stiff these > boards are even when they are being dry fit and pre-stressed for bearing. You wrote The buttress effect, again regardless of assembly stiffness, is so inconsequential as to be functionally meaningless.</BLOCKQUOTE> <<<<<<<<  This is what I was ineptly trying to say.  Th Th Th thanks Ron for clearing that up for  me.     You're <BLOCKQUOTE TYPE=CITE style="BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px">still talking about something like 0.003" rim spread from full crown to flat.</BLOCKQUOTE>      Dale wrote >>>>I'm not sure I agree with that. I'm about to press up an Stwy L board and  after it's pressed and crowned I'll measure across the bottom from each end of the longest rib and then I personally will sit or stand on  the board on the floor and see how far the rib dimesion expands. Hmm this might be hard to measure but I'm going to try anyway. Maybe I'l just make a mark on the floor at each rib end and visually observe. Ever done this? It seems to me that .003 figure would have to be greater for the crown to completely col.lapse Actually I see your point thought that even if the board/ribs were pressing significantly into the rim like a buttress the wood creep in the rim over time would still eventually be the crowns undoing. Still it seems like it would have to spread at least .050.           Ron wrote <BLOCKQUOTE TYPE=CITE style="BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px">You bend a rim more than that just leaning against it, so there's no way it will support board crown as a buttressed arch under the bearing loads the board is subject to. The PSI pressures involved are well beyond the yield point of the spruce even if you did have an absolutely rigid rim - which you don't. -=-=-=-=--==- > >    >>>>>>>> This is the false crown measured by piano techs that is mistaken > for real crown values. 1/8" crown on the logest ribs isn't really crown. As > you know  this false crown disappears as soon as the board is released from > the rim bevel. Exactly the point.</BLOCKQUOTE>     >>>>>>>>Hey I catch on quick after a long time.              >>>>>>>>>Dale>>>>>>>> <BLOCKQUOTE TYPE=CITE style="BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px"> .</BLOCKQUOTE> </HTML>