>It never occurred to me before, but today I have made up a trial inner rim >using laminations of three-ply birch, a wood visually and structurally >quite similar to maple. If I were shown this without knowing its >composition and without looking extremely closely, I would almost certainly >say the laminations were of birch-or-maple and mahogany or some similar >wood, so much does the end grain of the birch resemble mahogany in >color. I wonder if this is really the answer to the question after all. > >JD John, You don't suppose???? So why would Yamaha compromise the stiffness of rim laminations by (+-90°) cross plying layers? To what benefit, and at what performance cost? I would have thought (and still do) that the structural requirements of a bent rim would require nominally parallel grain amongst the laminations to maximize stiffness. Otherwise, why..........? This doesn't compute, and will distress me considerably if it proves to be the case. Since the remains of my visual acuity dictate that close examination is what I can do best, I'll check it out and get back with either a raspberry, or some flavor of despair. Ron N
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