This is a multi-part message in MIME format. ---------------------- multipart/alternative attachment ----- Original Message -----=20 From: Erwinspiano@AOL.COM=20 To: pianotech@ptg.org=20 Sent: April 26, 2002 1:28 PM Subject: Re: Soundboard Installation & MC You're still talking about something like 0.003" rim spread from = full crown to flat. 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.=20 =20 Ron wrote 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. -=3D-=3D-=3D-=3D--=3D=3D- > > >>>>>>>> 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. >>>>>>>>Hey I catch on quick after a long time. >>>>>>>>>Dale>>>>>>>> . ---------------------- multipart/alternative attachment An HTML attachment was scrubbed... URL: https://www.moypiano.com/ptg/pianotech.php/attachments/c3/aa/b0/63/attachment.htm ---------------------- multipart/alternative attachment--
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