>To: pianotech@ptg.org >From: jolly roger <baldyam@sk.sympatico.ca> >Subject: Re: plate reaction was Re: Pitch Raising to A440.......Or Not? > > >> Does the plate "flex" or "compress"...well yes without a doubt it does.... >>to some extent......... the question is 'which way'? > >Hi Jim, > Over generalization, Upwards I would say, thats why so many >pianos have nose bolts. Some pianos use just a plain lag bolt, others, the >more stable clamp type lag bolt. Working out all the tortional stresses in >a piano plate is highly complex, since the turning moments of force is >running in several different directions. ( String lay out and over >stringing) > >Your thought's on pitch and static friction, is probably correct. But any >calculation of static friction would just be a a calculated guess, since we >are putting the string into motion, Is this enough to break static >friction? From Ron. O's Experience of tuning rear duplexes, I think it >may be. His observation is that it takes 6months with regular tunings to >reach this state. > >So another question. As the string takes on a set, (bend around the pins). > Is the tansverse and longditudinal modes of the strings changing, due to >the bends? Thereby helping string rendering. > >Now I crawl back under my rock, since I am at a loss. > >Roger >
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