On 2/23/2011 10:49 PM, David Love wrote: >The belly of the Overs piano was very different in its weighting and hammer > requirements. While they both employ some similar features, I don't think > you can really compare the two in terms of panel characteristics or rib > scales. Ron O's pianos are more heavily ribbed than most, so the assembly will be stiffer. But the other component has been almost universally uncommented on. The panel adds considerably more stiffness to the rib support than most realize. Being a laminated panel is what makes this work so well. There is vastly less cross grain compressibility in this panel than there would be in a solid one. I built a demonstration model years ago. A roughly 800mmx200mm piece of old 5mm Yamaha crate plywood, sprung in a curve and a (one, in the center) straight 25mm wide x 20mm deep straight pine "rib" sprung into the curve and glued in. Both components are trying to straighten back out, but glued together, they can't. If the panel was cross grain solid spruce, there would be some obvious spring to the assembly as you pushed on it. With the more nearly incompressible plywood panel, the assembly is amazingly stiff. I have something like an 8mm crown in this thing, and a handy 215lb mass load that I happened to have around won't force it flat. Ron's rib scale on a solid spruce board wouldn't work anywhere nearly the same. Ron N
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