> I took the measurements of all the ribs, and the thickness of the > soundboard. Do the measurements need to be in MM's to do the deflection > calculations on Ron's handout? (I loaned it to someone, it's not right > in front of me). No, all measurements can be in inches if you prefer, or any other linear unit you like. The two formulas I gave differ in the unit of weight used for the MOE figure given in PSI. I included one formula for pounds, and one for Kilos. Deflection results will be in the same linear units used for input - inches, miles, millimeters, furlongs, parsecs, etc. > Interesting, that the thickness is much thinner at the bass end than > at the treble (at the edges, anyway). Like .235 at the bass end, to > .335 at the treble. Basses want flexibility, trebles want stiffness. I expect that's what they were doing. >13 ribs, most essentially square, with a little > difference around ribs 3-8, all a little taller than wide. > Ribs looked to be flat, so it's a compression crowned board, right? > Clark A. Sprague Don't know. Typically, compression crowning uses ribs wider than they are tall. They might have been flat originally, or crowned to a big radius. It's often hard to tell. Ron N
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