>Now I can understand the logic behind this with the CC guys, since they >are likely to achieve a higher crown when the panel re-hydrates. However, >in the case of rib crowned construction, wouldn't it be advantageous to >set the grain in the rib such that the growth rings are horizontal and the >medullary rays perpendicular to the sound board panel? Could be. I did a deflection test on a piece of spruce, 1.4 meters long, and 0.935" square (that's just how it came out of the planer. With a 10 pound box of tuning pins as a load, it deflected 0.008" more with the growth rings vertical. I tried all four sides up. I'd already decided that it doesn't seem to make any difference with laminated stuff, but with solid ribs, I've always tried to keep the rings over 45°. There may very well be no good reason to do so. I haven't found any data on differences in creep rates under load in beams with quarter cut vs flat cut wood. Compression yes, creep under bending load, no. Have you? Anyone else? Hammer shank manufacturers sure don't seem to consider it anything to worry about, though it's kind of hard to tell. >I am contemplating setting the rib grain this way for piano no. 004 If you do, I'd like to hear what you think. >(both 004 and 005 are now sold before completion, which is quite a relief). Good. I'm very glad to hear that. >We increased the cut-off rail section size to 50 mm wide by 35 mm deep, >using 17 laminates of 2.9 mm thickness. I typically use 60mm wide, but I come from a long line of compulsive over-builders. I have no idea what's best, but I figured it can't be too stiff. >I will try bending it with 4 mm laminates for piano 006. When cutting and >drum sanding the laminates at 3 mm it is quite wasteful of wood. I'll get >some photos of the buck and cut-off scanned and onto the website soon. > >Ron O. Or even 6mm. It's not a very tight curve, and you're anchoring it to the beams, so it can have a lower glue to wood ratio. <G> Ron N
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