>I am assuming that a serious sound board will be rib crowned, but a >laminated all spruce panel with rib crowning must surely be an excellent >combination. You bet. A wonderful combination. I didn't say it very well, but I was speaking, as I think Del was, of just the difference in material stresses between the destructive compression levels in a panel supported crown, and the much more benign stresses in rib supported crown, since spruce takes bending stresses much better, and for much longer than compression. I presume a laminated panel wouldn't be called upon any more than a solid panel for supporting string bearing by panel compression in a rib crowned system. Though, as you point out, it certainly could be with less cumulative damage than a solid panel. That's all I meant. >I am assuming that any piano maker worth his/her salt will be using the RC >process for crown. I cannot understand how anyone who claims to be serious >about piano manufacture would use compression crowning. Likewise, though load analysis of the rib sets being used and the bearing loads being placed on them (of those few I've checked) indicate to me that the panels are still carrying a significant percentage of the bearing load, even in some (most???) rib crowned boards. >Regarding the fit-up of flat bridges to crowned sound boards, as I think >one other technician mentioned on the list, we are talking strictly about >the fit-up of a logarithmic style long bridges. Hockey stick long bridges >truly are 'dust bin' technology. > >Ron O Absolutely, or sports equipment. There are better, if not cheaper, ways. Ron N
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