Bridge caps

[Delwin D Fandrich]

----- Original Message -----
From: "Greg Newell" <gnewell@ameritech.net>
To: "Master Piano Tech" <mpt@talklist.com>; <pianotech@ptg.org>
Sent: September 08, 2001 7:50 PM
Subject: Bridge caps


> why not attach the rails
> directly onto the underside of the router plate and let it ride on that.
> More like a sort of free hand approach. Would this be unstable? Would it
> possibly eliminate a straight rail not mating quite so perfectly to a
> crowned board?

I've done this both ways and both work. I actually prefer the method you
describe. You do have to be careful to not mar the soundboard finish
(unless, of course, you are refinishing the soundboard later), but you can
do this by taping off the area the spacers are going to ride against.



> In your drying process are you left with a completely
> flat board and therefore this is not an issue? If this is the case how
> do you maintain the moisture content of the board while you are
> performing the various procedures on the bridge?

Unless you place the whole piano in a conditioning room there is really no
practical way to maintain some particular moisture content in the soundboard
while you're working on it. Nor is there any reason to do so. For reasons
that have been discussed previously on this list it is impossible to restore
any crown to a collapsed soundboard during the repair process. If you're
using wood shims and/or inserts to repair cracks in a soundboard you should
dry both the soundboard and the shims to approximately the same MC and that
MC should be at the low end of any reasonable MC the soundboard might
encounter in its future life.



> If you followed a
> crowned board then would you have difficulty attaching a replacement cap
> to what would then be a crowned bridge base?

No. The curve in a crowned soundboard--especially one old enough to be
requiring a new bridge cap--will be so slight that any bridge cap of
reasonable thickness will have no trouble following it. Nor will a complete
bridge for that matter.

Del