[pianotech] Rebuilding tips

[David Love]

I generally use the original root so it doesn't really go through the
planer.  I remove the old cap in one piece when possible, fill the old
bridge pin holes and then just sand or scrape it flat.  If the root varies
in height it's not much and is usually a gradual taper.  I do the cap on the
long bridge in three sections: 1st capo, 2nd capo, tenor.  Any variation in
the root height in each one of those sections will be small and if necessary
I graduate the cap height in each section with the rough cut and then sand
to final height.  I don't always use laminated caps but when I do I don't
use delignit but rather keep the laminations fairly thick (maybe 3mms?) so I
can still notch by hand.  

BTW I use this same process when installing new bridge caps on a piano where
I'm not changing the board.  In fact, lately even when putting in a new
board I've been attaching the bridge root to the board and gluing the board
into the rim before I start measuring for the cap thickness.  Part of the
reason is that I like to have the board glued down to the cutoff bar (which
there always is on new boards that I do) and have the perimeter bolts in
place before I measure and cut the cap.  I'm so used to recapping bridges on
existing boards that it almost feels more comfortable to work that way
anyway.  The only downside is that it can be a bit harder on the back.  Of
course, if you are using a power notcher then you have to notch the bridge
before it's glued onto the board and therefore have to do everything with a
dry fit.      

David Love
www.davidlovepianos.com

-----Original Message-----
From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf
Of jiimialeggio
Sent: Wednesday, January 13, 2010 5:02 PM
To: pianotech at ptg.org
Subject: Re: [pianotech] Rebuilding tips



> I take the other gauge and slide it under the string on top of the 
> uncapped bridge until it just touches the string. That gauge, btw, is 
> made about the width of the bridge pin array-though it doesn't really 
> matter, it should positioned ideally where the strings would be 
> touching the bridge. Whatever the thickness of the gauge is at that 
> point is the thickness of my bridge cap. I do this along the entire 
> bridge every whatever marking on the bridge top the thickness of the 
> to be made cap. Then I make the cap to the desired thickness usually 
> with the front edge of the bridge about 1 mm higher than the back to 
> insure positive front bearing-this may vary depending on the piano 
> though.
>
>
> David Love
>
David,

Interesting posts...

Am I correct that you leave your root top surface as it came out of the 
planer, and make your cap vary as necessary? If so, with your laminated 
cap do you do this by building it up unevenly as necessary and then sand 
to finish dim?

Also, sounds like your using laminated caps. How are you notching them? 
Did you make yourself a machine, or are you pulling it off by hand?

Jim I