Soundboard Thinning

[Delwin D Fandrich]

----- Original Message -----
From: "Farrell" <mfarrel2@tampabay.rr.com>
To: <pianotech@ptg.org>
Sent: February 16, 2002 7:30 PM
Subject: Soundboard Thinning


> Regarding area-specific thinning of the soundboard edges. Do you do this
after gluing on ribs or before? If done before gluing on ribs, does this
cause concern regarding the radius of your rib-to-soundboard gluing caul -
that is getting the proper radius - it would tend to flatten the bottom of
the board (and the rib) out when gluing up in the caul - unless of course
your caul has some kind of a compound curve cut into it to compensate for
the thinned soundboard. If thinned after gluing up ribs, no problem gluing
on the ribs, but then you have this funky dome/tunnel thing squirming around
while you try and run a big plane across it. What's a guy to do?
>
> Terry Farrell
>
>

Ignore it. There is nothing all that magic about a specific crown radius.
I've never measured a board with a 60 ft. (approx. 18 m) crown radius
anyway. The board, at least in our shop, is thinned before ribbing. Bear in
mind we only thin along the bass end of the board and then only if we're not
floating the back end of the board. If the back end of the board is
floated--i.e., cut free--there is no need or benefit to thinning at all. We
do not thin out the treble or tenor areas.

Del