At 11:15 AM -0700 22/7/02, Phillip Ford wrote: >. . . What is desired is light but stiff ribs. >Structurally speaking, the dimensions that would most efficiently result in >that would yield a rib that is narrow and tall. Its a good point Phil. This is an area of investigation to which, I suspect, more attention should be focused. > But the typical rib is about >as wide as it is tall. Do you think this was to provide enough glue area to >keep the rib attached to the board when building a compression crowned board? At 10:19 PM -0700 22/7/02, Delwin D Fandrich wrote: >Depends on how the soundboard is crowned. In a compression-crowned >soundboard the ribs must remain flexible enough to be forced into a crown by >the expanding soundboard. In these systems the ribs actually resist the >formation of crown and fight it for the duration. Indeed, for the CC brigade, there's not much evolutionary development possible since short ribs are a necessity. > In a rib-crowned >soundboard system the designer has a few more options. And, yes, gluing area >does become an issue if the ribs are made too high and too narrow. One of the first pianos which got me thinking about this area of tone building, early in my career, was the quality English manufacturer Sames. I feel sure there was quite some interest in this topic at the Sames factory, since I have seen them use many different ribbing approaches (including fanned ribbing). Many of their designs were clearly focused at securing a stiffer rib with less weight, while retaining a respectable rib to panel gluing area. Whenever a Sames is encountered, it is often worth sneaking a look 'round the back'. Ron O. -- _______________________ OVERS PIANOS - SYDNEY Grand Piano Manufacturers Web: http://overspianos.com.au mailto:info@overspianos.com.au _______________________
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