Yes, better, thank you. As one guy building soundboards, I'm not sure how to use this info. but it helps me to understand the system. IS there a force pushing the rim out, and is there any advantage to trying to make that rim immoveable, and is there a consequence to it moving with respect to the soundboard? ----- Original Message ----- From: "Ron Nossaman" <rnossaman at cox.net> To: "Pianotech List" <pianotech at ptg.org> Sent: Friday, April 14, 2006 9:28 AM Subject: Re: Buttressed Arch. Question for Ron N. > > > I don't KNOW, Ron. But if you keep talking I'll shut up and listen. If my > > brain were as flexible as Sitka, I'd be fine. > > Thanks, > > Fenton > > > When you bend a piece of wood (rib), the fibers on the convex > outside of the bend are stretched, and the fibers on the > concave inside of the bend are compressed. So if you glue an > expanding panel on one side of that piece of wood (rib), it > will stretch the rib's fibers at the glue joint as it expands, > bending the rib. Bending the rib stretches the fibers on the > outside of the curve (top), and stretching the fibers on the > top face of the rib causes the rib to bend and increase crown. > It's that simple, and has not a thing to do with an arch. The > panel will still rise and fall with humidity swings because > the compression level in the panel changes with it's moisture > content, and the resulting degree to which it stretches the > top side of the rib changes with it, changing the crown rise > as a result. Still no arch involved, it's a self contained > leverage that works without end buttresses. > > Better? > Ron N > >
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