laminated ribs

[William R. Monroe]

Terry,

Just looked again at the previous post.  Looks like not much deflection on
the upper go-bar deck is likely for you.  What is that, 8/4 pine?

Inquisitively,
William R. Monroe



----- Original Message ----- 
From: "Farrell" <mfarrel2@tampabay.rr.com>
To: "Pianotech List" <pianotech@ptg.org>
Sent: Sunday, February 19, 2006 6:42 PM
Subject: Re: laminated ribs


David M. Porritt wrote:

While you have an unstrung board is it possible to put weights on the bridge
approximating the downbearing load you expect to have then reexamine the
crown and bearing angles?  Would this give an elementary idea of the board's
ability to sustain that load?

Yes indeed. I consider that to be an integral step to setting up a new
soundboard. I use go-bars to apply down-force to the bridges (see the
picture below). I calibrate the go-bars by measuring the go-bar pressure
with a scale (see second picture - my wife keeps bugging me: "Terry, where
is the bathroom scale?"). I suspect that after one has built and set up
many, many soundboards, this step may not be necessary. But I find a
tremendous educational dimension to the process.

Terry Farrell