PIANOTECH digest 284

[Larry Fisher]

>
>From: dreemer@crl.com (Chris Olson)

>Subject: Broken bottom board on Upright

.  The bottom board has a major crack along the whole
>length of it in the middle where the pedal screws go into it.

 So, I'm thinking - replace the bottom board.  Now, since I haven't
>done this before, this is where I have the questions -
>
>What kind of wood should I use?
>
>About how much time should I estimate for the job (including removal &
>replacement)?
>
>Any ideas on the best way to make a template for pedal placement?
>

>Chris Olson
>Complete Piano Services
>Sebastopol, California
>dreemer@crl.com

I've doweled the old one back together in the past.  A set of doweling jigs
is fairly cheap, and having never done any edge doweling before, I had
really good results on my first try.  The end result is a stronger than
original repair and you don't have to deal with slightly relocated holes
during the replication process.  Any screw holes that are worn out or damage
due to the location of the crack can then be drilled out and doweled.

A doweling jig consists of two pieces of metal that look like a top hat.
The wider end has a tip or small point that represents center.  Drill a hole
in one side of your repair piece matching the diameter of the smaller,
narrower end of the jig, and insert the jig in this hole.  Now match the two
work pieces up, (mate them) and press or hit with a mallet hard enough to
make a dimple in the matching work piece, directly across and in line with
the hole you just drilled.  I've put as many as four in a bottom board,
doing them in pairs.  Once two are established the rest are easy since you
use the first two as guides, using dry fitted dowels.  You could sand them
down slightly so that they slip in and out of the holes easier if you'll be
doing several more.  Now glue everything.  Apply liberal amounts of glue on
the joint as well as the dowels and clamp.  Be sure to keep the board flat
as you go.  Clamping a 2X4 across it (the short way) helps prevent warpage.
The dowels will help keep it straight, and when it's mounted back in the
piano will help flatten it out some more.  Keeping it flat during the
glueing process helps generate as much surface contact as possible making
for a really strong glue joint.  This is all fine a good providing the joint
is flush when the boards a flat.  Some boards warp in weird ways.  Checking
for such things during a trial run or dry fitting is a good idea.

Time to do all this?    Somewhat less than total replacement.  There's no
relocating, no replicating, very little regulating, and virtually no
compensation for ever so slightly relocated holes.

Charge?  2 hours I think.  A tipping cradle is essential.  An electric
screwdriver or a screwdriver bit in an electric drill save oodles of time.
Replace any worn or messed up screws.  A flat work space is handy.  This can
all be done in the home on a nice day when you can set up some saw horses in
the yard and some 3/4" plywood for a work bench.  Bring lots of clamps, and
put down a moving pad on the floor before you tip the piano over.  It will
catch all the tasty stuff that will spill out when you remove the bottom
board.  As the glue sets go to a long lunch or do other calls.  Then after a
few hours come back, and reinstall gently.  The dowels will hold the boards
together, and the screws that hold the bottom board to the piano will hold
the rest.  Use a wet rag to wipe the excess glue off the bottom and place
newspaper under the piano in case any more seeps out.  This in home
proceedure should only be used if the piano is some distance from the shop.
I prefer to do all this sort of thing in the shop.  Having serviced the 8
hrs from home type of Wyoming countryside in the past, I'm always thinking
of ways to cut expenses, return trips and return the piano to playable
condition as fast as possible.

Cheers

Lar


                           Larry Fisher RPT, Metro Portland, Oregon's
                  Factory Preferred Installer for MSR/PianoDisc Products
                       phone 360-256-2999 or email larryf@pacifier.com
                            http://pacifier.com/~larryf/homepage.html
                         Beau Dahnker pianos work best under water