Soundboard Edges

[Delwin D Fandrich]

----- Original Message -----
From: "Farrell" <mfarrel2@tampabay.rr.com>
To: <pianotech@ptg.org>
Sent: February 16, 2002 3:29 PM
Subject: Soundboard Edges


> While driving to Mt. Tabot Missionary Baptist Church this morning I had to
turn off the radio and try and come to grips with the edges of a new
soundboard. Let's say you make a 60-foot rib-radiused board (60-foot - the
radius, not size of the board). OK, so now you have this little dome with a
height of maybe 3/8" or so in the middle. (Or maybe you make one with
smaller radii, so you have more crown - whatever.) The top edges of the
piano rim and belly rail are at the same elevation - in the same plane.
-------------------------------------------------------


Ron's answer covered most of it, but....

Kimball, and probably others, developed a process to crown their grand piano
inner rims to accommodate a spherically shaped soundboard. This has long
been a common practice with vertical pianos--the soundboard liners are
crowned to accept the soundboard in a spherical shape.

The soundboard will still be distorted for reasons that will be obvious if
you think about it a bit.

Del