evaluating sdbd. crown & bridge downbearings in a new piano

[Ron Nossaman]

>>The curve is taken on because the top of the board is able
>>to expand somewhat to relieve the excess compression.  The bottom of the
>>board is glued to the ribs and does not have the luxury of expanding to
>>relieve compression.
>

>Thus the bottom of the board is in more compression than the top.  One might
>conclude that the stress due to deformation which subtracted from the
>compression in the top of the board and added to the compression in the
>bottom acted as tension in the top of the panel and compression in the
>bottom.  Think.  If the board were equally compressed top and bottom, where
>would the moment come from to cause it to take a crown.
>
>Frank Weston


I don't see how one might conclude any such thing. The compression at the
top of the panel isn't acting like anything at all other than compression.
Think, and remember. No one has ever even hinted that the panel is equally
compressed at the top and bottom. It has been stated a number of times that
the panel is compressed more at the bottom than at the top, but the entire
panel is, inescapably, compressed. There just isn't any way around it.

 Ron N