Richard Moody wrote: > > To Delwin and List > Some where along the line I heard that some makers used wedges > between the sound board and rim ( in stratigic places) to help "shore > up" the crown. Is this true? Or was I dreaming? > Richard Dreamon > > ---------- It's quite possible. A lot of things like this were tried that didn't work. The only technique that I'm aware of that did at least partially work was the arrangement developed by J. Bauer in which the soundboard was mounted on a separate rim that was attached only to the plate. The outer rim was a totally separate structure. In this case we have to say that the inner rim was attached to the plate and not the other way around. The plate was the main structural member. An by itself, it was about as heavy as most pianos of the same size. Anyway, it was fastened to the plate in a more-or-less conventional manner by using closely spaced screws coming down through the plate, a spacer mechanism—I’ve forgotten now whether dowels, spacer blocks or a top liner was used—and into the inner rim. The plate was a "full-parameter" plate in that the inner rim was mechanically fastened to the plate all the way from the upper bass corner to the treble corner. The “belly rail” was integral to the inner rim and was not attached to either the outer rim or the keybed. The plate extended down between the two rims and adjustment bolts were installed in the plate the heads of which bore against the inner rim. These bolts could be tightened against the inner rim and to some limited extent made the crown to the soundboard assembly variable. The only reason that this scheme worked at all was because Bauer also used what I would call a "half-rib" on each side of the soundboard. In other words the rib was made of two pieces one on top of the soundboard and one on the bottom. In “modern” piano construction nothing done to the parameter of the soundboard is going to “shore up” soundboard crown—including the Mason & Hamlin centripetal tension resonator. Crown is lost because wood fiber crushes and creeps over time. No amount of strategically placed wedges is going to change that.
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