Well, as King Agrippa said: "Almost, thou persuadest me ... " And, yes, it was just my suppostition. But something has to explain the source of change in old pianos that have had all the time necessary for the soundboard to collapse, strings to stretch, etc., as much as they possibly could. But still fall flatter if left alone for long stretches. Somebody with a physics background might be able to define the static and dynamic forces involved here, say 125 to 175 lbs. of tension on a rope (sting) attached to a pulley (pin) with a counter-torque friction of 35-200 in. lbs., etc. Happy Easter/Passover/Whatever/Birthday/Nothing (pick one) to all! Alan R. Barnard Salem, MO -----Original Message----- From: pianotech-bounces@ptg.org [mailto:pianotech-bounces@ptg.org] On Behalf Of Ron Nossaman Sent: Sunday, March 27, 2005 2:16 PM To: Pianotech Subject: Re: Aha! was flat facts > And herein lies the interesting crux of my whole question from the > beginning: We have guesses, suppositions, and opinions but, > apparently, really don't know why pianos get flatter and flatter and > flatter over time. Seems like this question is so basic that > experiments would have been done long ago and we'd have a definitive > answer. And maybe, who knows, some ideas for building more stable > pianos. There have been experiments, including making pins so tight in waterproof pinblocks that you could barely turn the pin in with three hands. Guess what. The super tight waterproof block pianos still dropped in pitch over the long run. In my experience, tuning stability gets better with decent scaling, rib supported boards, and laminated bridge caps. Hence my answer. > I still go with turning pins, though. There is a natural, sustained > tension on the pin from the string that would love to turn the thing > counter-clockwise. Earth tremors, children thudding across the floor, > sonic booms, moving the piano, and hovering ufo's would all put > vibration into the system, however briefly, and the pin could jiggle > just a a third of a skinny hair each time. But over the years ... Is that a guess, a supposition, or an opinion? Just asking, since the same rules ought to apply to us all. Ron N _______________________________________________ pianotech list info: https://www.moypiano.com/resources/#archives -- No virus found in this incoming message. Checked by AVG Anti-Virus. Version: 7.0.308 / Virus Database: 266.8.3 - Release Date: 03/25/2005 -- No virus found in this outgoing message. Checked by AVG Anti-Virus. Version: 7.0.308 / Virus Database: 266.8.3 - Release Date: 03/25/2005
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