Del said: "I suspect success or failure depends more on how the original pinblock is used as a structural member and on how the original block responds to changes in moisture content. In those plugged blocks I've encountered that have failed (and I'm going by an increasingly failing memory here) the mass of plugs was pulling away from the front (i.e. toward the front of the piano) of the block. There were also numerous small cracks opening up around the plugs throughout. I did not consider these to be structurally significant, just visually annoying. Veneering over the top of the mass of plugs may have rendered these invisible and I don't know that they were significant enough to have telegraphed through the veneer and become visible. I can think of several reasons for this failure. Most obviously the tension on the strings, hence the pins, may simply exceed the structural capabilities of the pinblock design and assembly. Since one of these pianos was a Chickering similar to the one you refer to I suspect there may have been quite a lot of rotational stress on the mass of plugs. This may not be a factor in a pinblock designed to keep the line of stress more directly in line with the strings. The other problem I see with this technique is with the aforementioned physical changes that might be taking place in the original material due to varying levels of moisture content. One of the plug failures was in an original block made almost entirely of one single piece of maple. The mass of plugs, along with its requisite bath of epoxy, is going to be relatively stable regardless of changes in relative humidity. The original block, however, is going to continue swelling and shrinking just as it has for the past 137 years. And no adhesive known to mankind is going to prevent the two from separating. (To diverge down the bunny trail a bit: And we wonder why all these" Del, I completely agree with all of the above. It is solely dependent on the overall structural integrity of the block AND the piano! Case in point: The last soundboard you did for me, was a real bear for you. The piano was of substandard basic construction. You had to do a lot of extra work, just to fit a new soundboard, etc. This was a "Restoration", so original scale tensions were adhered to, on my part. As I was just finishing up the plain wire stringing, a HUGE "KERRRACK"! occurred!!!!! Yikes!!! (Said I.<G>) Because of the substandard case design, the cheeks decided to go East/West!!!!!!! I had to resort to some rather bazar damage control. This consisted of a 1/2" acme threaded rod, inlet into the underside of the pinblock and through the case sides. Coupled with huge washers and appropriate nuts. Every clamp I owned, buckets of glue, epoxy and doweling went into the damage control project. The scale was RE-evaluated and slight modifications were done. The nuts/washers were covered with Rosettes that were made to match the lid lock knob. The piano is owned by a close neighbor, so I get to keep a close eye on it. The customer is delighted that the piano was resurrected and plays it constantly. So far, all is well, but it's like walking on egg shells, from tuning time to tuning time. On this one, only time will tell. I know that and so does the customer. Bottom line: if the initial structure is not sufficient to be brought back to BETTER than it was originally, the plugging system will fail. In this particular instance, if the customer gets 20 years of enjoyment out of this "Restored" 1865 instrument, he'll be a happy camper. Well, so much for baring my rebuilding soul, so to speak. BTW, the overall sound and touch of the piano is soooo 1800's, even tho major modifications were made in the rebuilding process. I get a warm and fuzzy feeling every time I work/play on the piano. I guess having fingers crossed is becoming my habit on this one.<G>(although, it's difficult to play that way.<G>) Best Regards, Joe Garrett, RPT, (Oregon) Captain, Tool Police Squares Are I
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