Fwd: Re: plate reaction was Re: Pitch Raising to A440.......Or Not?

[jolly roger]

>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 
>