At 11:19 AM 12/4/98 EST, you wrote: >Greetings, > Stephen writes: > >OK, so I got some questions> (?:}} > > I would like to ask, is that rib correctly regarded as only a "beam"? *Yes, and no. In a system using machine crowned ribs, the rib stiffness helps support the crown and string load. In a compression crowned system, the rib works against the crown. In either system, the rib acts as a cross grain expansion constraint to the panel. >Is >there no "arch" aspect to the manner in which downward force is vectored >outward? * No, it's an entirely different and self contained thing. Read the December 1997 PTJ, page 32; Soundboard Arch. >What is the centripedal resonator actually doing in those Masons? * Stiffening the rim and increasing it's mechanical impedance. It has nothing to do with forming or maintaining soundboard crown. There may also be a dim possibility that it scares mice away, but it's hard to prove. > If a board rises up when being destrung, is it because the soundboard is >losing compression across its grain and expanding? * In a compression crowned assembly, yes. In a rib supported system, it's also the elastic recovery of the ribs. > Or are the edges coming in >with the case in the absence of downbearing pressure? * No, they aren't. A soundboard crown is not a conventional arch. >Wondering on the weekend >Ed Foote >(also puzzling over the strangest stringing scale I have ever seen, can't wait >to try it!) > * What 'cha got? Ron
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