>Yes, but few bridges use cross-ply laminated construction. And I question >defining the 'traditional' 3-ply and 5-ply type pinblocks as cross-ply >laminates. ---------------------------------------------------- >I suspect it has more to do with the relative coefficient of friction >between the wood fibers of the pinblock and the metal tuning pin at various >wood moisture contents. > >Del The three and five ply pinblock pretenders may not make the cut as optimal cross ply laminates, but the layers are constrained cross grain. It doesn't take much in the way of constraint to dramatically increase the internal compression levels of the "laminate" layers. Compression crowned soundboards come to mind, and their expansion constraint is under 10% of the surface area of one side of the panel. The internal pinblock laminae have 100% surface constraint on both sides - with only one side constrained top and bottom. I still see those holes getting smaller as the wood expands. Bridges are a little tougher. There's a good chance that the assumption (mine included) that bridge pins get tighter in high humidity is wrong, based on the fact that loose pin related false beats are less obvious in high humidity cycles. They may very well not get tighter at all. I really don't know, because I never directly checked. The soundboard should logically rise some though (though I haven't actually measured that one either), and the bridge will get taller and push the string up the pin some. The bearing will be greater, the termination will be firmer, and the false beating should be less as a result. Something else to get around to trying to test. Back in the late 60's, I think, everyone got all excited about resin impregnated wood (for about two weeks). It was hard as a by-gosh, impervious to moisture, buffed to a high gloss after machining without any additional finish, and was going to revolutionize EVERYTHING if they could just get the cost and vacuum processing cycle time under control. I guess they never did. Too bad. It might have been just the thing. Ron N
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