[pianotech] new board evaluation

[David Love]

Having to pull the board down on the bass or treble side is typical.  You
can clamp the board beyond where the plate ends on the straight side and
screw it down everywhere else while you are determining the bearing.  If you
put screws through the rib ends you don't have to worry about splitting the
panel.  

Although many people like to cut and notch the bridge before installing the
board I have recently started capping the bridge after the board is glued
in. It's a bit more trouble in one way but it's not unlike recapping a
bridge on an existing soundboard assembly.  After attaching the bridge body
to the panel and gluing in the board, I install and level the plate and then
I have a method for determining the bearing and the thickness of the cap
before I make the cap.  Once that is done I make the caps and cut them to
the predetermined thickness plus a mm or so.  I cap the bridges in the piano
and sand the caps the final mm to the correct height, lay out the bridge pin
array and drill and notch in the piano.  I have a had a couple of
experiences where my determining the bridge height before the board was
glued in didn't quite coincide with the post glue in measurements so I've
gone to this method--even with a floating perimeter and vertical hitches it
just suits me a bit better.  Lots of ways to do it though.  

David Love
www.davidlovepianos.com


-----Original Message-----
From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf
Of Gene Nelson
Sent: Sunday, December 07, 2008 4:44 PM
To: pianotech at ptg.org
Subject: Re: [pianotech] new board evaluation




> I'm curious to know more about why the rim needed to be built up.  Why do
> you that part of the board wouldn't go down very well?
I could have forced the board down with clamps at glue up I suppose, but I 
thought that doing this would greatly contribute to its stiffness. Also, in 
order to set bearing I needed to have the board down on the rim all the way 
around. Clamps were not an option with the plate in so I used screws. The 
screws would have split the board if I tried to use them to pull the board 
down.
If I had my way I would have cut off the board at the first bass rib and it 
would not have been an issue.
Gene