Too Much Crown?

[Delwin D Fandrich]

Terry,

I'm going to guess that this soundboard might have been made using crowned
ribs.  (Yes, there were some enlightened builders in 1890 [or so]).  If you
have this kind of crown with this many cracks and other soundboard damage
there must be some kind of curve machined into those ribs.  If so, you're in
luck.  You should be able to put the board back together and come up with
some type of soundboard acoustical system that will work.

(By the way, I'm writing an article that relates to this subject.  It's not
finished yet, but if you are not too far along with your project you might
be interested.  Let me know.)

Del

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----- Original Message -----
From: "Farrell" <mfarrel2@tampabay.rr.com>
To: <pianotech@ptg.org>
Sent: September 11, 2000 2:40 PM
Subject: Too Much Crown?


> Help! I just tore down a 1890 (or so) Estey 4' 10" grand. the other day.
It
> is actually a VERY heavily built piano - lots of framing. It is
> full-featured - four sections, agraffes & capo.
>
> Anyway, the problem. The soundboard is totally trashed. It is really
cracked
> and the edges between planks are warped up where they have separated from.
I
> have been drying the soundboard for about a week with a damp-chaser rod
> underneath and sheets on top (real nice in there - about 95 degrees and
30%
> relative humidity). I was routing out four or five of the 8 or 10 MAJOR
> cracks when B-O-I-N-G, the tenor end of the treble bridge springs up and
> just about sent me through the roof. The bridge end came up with a big
chunk
> of soundboard so that now there is a 1/4-inch gap between the soundboard
and
> ribs at the tenor end of the treble bridge (soundboard is cracked both
sides
> of bridge). IT'S HUGE.
>
> I stared at it for a while trying to figure it out. Got a string and a
> straight edge out. Under the soundboard with the string measuring
> perpendicular to soundboard grain and parallel with ribs, there is about
1/4
> inch of crown in board (not really a crown, but rather a "V" with the apex
> under the treble bridge). Put the straight edge parallel with and adjacent
> to the treble bridge and WOW there is a whopping 11/16" of crown parallel
to
> the soundboard grain and perpendicular to the ribs. If you sight down the
> treble bridge, it is fairly straight. It would appear that this is why the
> bridge end sprung up.
>
> I guess my question is if I bend the &$%#*@ out of the bridge, block the
> ribs up (hey, we can put even more crown in this puppy!) and glue the
> ribs/soundboard/bridge sandwich back together what might I have? Will it
> likely stay together? Will this do something really wierd to the
instrument
> sound?
>
> Before you pros tell me what needs to be done, I know (new board, bridges,
> etc.). That will not happen for about 10,000 reasons no one want to hear
> about. Either I will fix what is there, or I will have to tell the owner
> that it cannot be fixed (the owner is capable of understanding zero - I
have
> tried in the past - she says "well, just do the best you can"). A large
part
> of what is bugging me is that I really don't want to have my finger prints
> of this one, but I am in too deep now. :-(
>
> Terry Farrell
> Piano Tuning & Service
> Tampa, Florida
> mfarrel2@tampabay.rr.com
>