1977 Yamaha U1

[Ron Nossaman]

><<I know, I'm a pain in the... but could someone please explain to me how
>they can possibly imagine a couple of loose plate bolts making a piano go
>sharp (throughout the scale) suddenly. This is a story I just have to
>hear.>>
>
>I've been thinking about this, and will admit that it would have little, if
>any, bearing on sudden pitch changes. I was wondering, and still am, if it
>would make *any* difference at all.
>
>John Formsma

Hi John,
Better late than... well, late anyway. It would probably make SOME
difference, and it might even be detectable. Whether it would be a long
term tuning stability problem or not is the question, and I doubt it. It
seems to me that if loose plate perimeter lags caused pitch changes, then
tightening these loose lags should also cause pitch changes, no? With the
tuning world being chock full of highly accurate electronic pitch measuring
devices and a veritable fetish for tightening plate lags, there should be a
hundred or so curious souls who could take a little time to add to the body
of research and make some pitch measurements before and after the
"Tightening O The Bolts" ritual. Rebuilders could easily enough make a few
pitch measurements and loosen a few bolts before teardown to see what
happens too. 

There has been plenty of speculation and unsupported supposition about this
through the years, but it seems to be hard to get anyone interested in
actually trying to find out. Pity too, we might learn something useful.

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  An English professor announced to the class: "There are two words I
don't allow in my class. One is gross and the other is cool."

       From the back of the room a voice called out, "So, what are the
words?"


Ron N