>FWIW - I've noticed on many boards that even when positive crown is >present, there often will be an inch-or-two wide swath of negative crown >adjacent to the rim. I guess from the ribs being thin there. I presume so. >I wonder what, if any, consequences there may be to this. > >Terry Farrell Probably nothing you can directly correlate to something you can hear, other than a general deterioration of the board. Which brings up a point I've wondered about for a long time. Why are ribs most often feathered like that, regardless of whether the assembly is compression or hybrid compression/rib crowned? No self respecting structural engineer would design a controlled deflection load supporting beam that way. Too high stress concentration on the ends for the section profile. Very non-uniform stress distribution for something that's supposed to support a substantial load, perform dependably and last a while. Ron N
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