>Hi Chuck. I don't specialize in S&S, but I'll stick my neck out anyway (you do have a delete key, correct?) - and take everything I write with a grain of salt. My best guess is that the plate webbing was flat when cast in Springfield, Ohio. The string tension over the years has bowed the pinblock and plate along with it. Maybe the pinblock had come unglued from the stretcher (not that the stretcher has much strength anyway) contributing to the ability of the string tension to bow the plate/pinblock. Are we sure the plate isn't cracked - like a fore-aft strut, again allowing movement? I don't know how common a 1/4" warp is. >I know such warping is common on real old pianos that didn't have a full plate (I'm talking 1850s or so when you had a hitch plate and fore-art struts bolted to the hitch plate and otherwise unstiffened pinblock). >Did the string heights reflect the 1/4" warp? Perhaps a good way to tell if the warp was original would be to measure original pinblock thickness accurately. You state that the original pinblock was shaved down on the ends to conform to the bowed plate. Do you say that based on thickness measurements, or simply because the block mated to the plate (the block could be warped just like the plate)? Or did you measure the block and found that it is 1/4" thicker in the middle and tapered on the upper side to mate? Is the block shape a plane on the bottom? Thanks for the input, Terry. No, the pinblock was definitely altered at the factory to fit the plate. The pinblock is flat on the bottom. You can see where they planed through the layers of lamination to taper the ends. Frank, (who brought me the plate and original pinblock to copy) said that everything else about the piano appeared normal. It wasn't until they had pulled the plate, and removed the pinblock that they noticed the unusual curvature. I'm planning to plane a new block to match the old, unless someone tells me that's the wrong course of action. Chuck -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://ptg.org/pipermail/pianotech.php/attachments/20090915/0bc396ba/attachment-0001.htm>
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