Grand damper install

[Jim Coleman, Sr.]

On Thu, 11 Jul 1996, Jeff Stickney wrote:

>         I am about to install a set of dampers with new wires on a grand
> piano.  The only time I replaced wires before this, I used the old wire
> bends to get started with the new wires and went from there, but the
> existing wires on this piano have been so abused I can't really use them as
> samples.
>
> Jeff Stickney, RPT
> University of Montana
> jpage@selway.umt.edu
>
>

Dear Jeff:

I am assuming that you are installing new heads also.  If the new wires
are already swedged into the head, that's good.  The insertion process
usually involves either glue or varnish to seal and secure.

The length of the first bend from the head determines how far the damper
head is offset to the right or left of the guide hole. The reverse bend
insures that the damper wire portion which passes through the guide hole
is parallel to the sides of the damper head.  The next bend determines
the amount of offset from the guide hole to the center of the damper
upper lever.  This bend should be about 1 inch below the guide rail.
This bend will usually graduate through the tenor section.
The next bend which is about 1 inch above the top of the damper upper
lever is made to make the wire parallel with the upper lever wire hole.

It is best to glue on the damper felts to heads first.  Be sure that you
run a pencil line along the side of the tricord felts before you chop
them apart, so that if one side of the tricord is slightly thicker than
the other, you will have the marked side glued on the same for both front
and back damper felts.  This greatly simplifies the final alignment.

Once you have the wires in the ball park, you can cut them to proper
length so that they don't bottom out in the upper levers and so that they
will be at least 1/4 inch below the set screw when the damper lever is
at the proper height and the felt is resting on the strings.

There are 4 primary things to consider in damper regulation which involves
bending:

         Walk     Controlled by upper bend 1 inch below guide rail.  The
                     wire above this bend must be perpendicular to keybed
                     Any change here will require an opposite change in
                     the lower bend 1 inch above the upper lever.

         Twist    Twist wire above lever after screw is set so that
                     neither front nor back felt twists as it rises.

         Rock     Lift/rock damper forward or back till both felts seat
                     and come off the strings at the same time.

         Offset   Increase/decrease length of first short bend to center
                      dampers over strings.  There is a simple way to do
                      this in the piano.  Call me at 602 966-9159 eves.

         Lift     Set and reset screws lightly till all dampers lift at
                      once.  Set one or two in each section by a gauge
                      which is one half the hammer blow distance.  If
                      you have used new lever board felt, you should be
                      able to set the rest to lift at the same time.
                      Then tighten screws and repeat above items as
                      needed.

All of the above may make them look good, but they still have work.
Harmonic analysis of the result of staccato key blows will help determine
touchup needs as far as thick and thin sides of tricords are concerned.
Call me if you need tips on analysis.

Jim Coleman, Sr.

PS  There are many specialty tools which make this job run easier. These
are just the basics.