Spurlock Damper Design

[Farrell]

I have been contemplating the sequence of procedures I would use to
construct a set of dampers and the best I can come up with is as follows:

1)  Cut appropriate number of 1/8" thick X 3/8" X 2-1/4" (or whatever length
you decide) damper boards.

2)  Cut 3/8" wide felt damper wedges, etc. into 5/8" lengths (or whatever
length you decide).

3)  Glue felt to board, being real careful with felt piece alignment
(perhaps best to use a jig for training).

4)  Line up dampers side-to-side, felt side down, and glue 1/8" thick spring
rail felt to back of dampers boards.

Is spring rail felt the best to use (that is what Bill Spurlock uses)? What
about muting strips - they are available in various thicknesses - perhaps an
advantage to get best fit? What about understring felt - or is that too
firm? What about action cloth - again, available in various thicknesses? Or
any other felt work best? Any thoughts? Thanks.

Terry Farrell

----- Original Message -----
From: "Dale R Fox" <foxpiano@juno.com>
To: <pianotech@ptg.org>
Sent: Thursday, August 30, 2001 10:53 PM
Subject: Re: Spurlock Damper Design


> Hi Terry,
>
> You can use aircraft ply available at the local hobby shop if you want
> better stability than solid basswood.  Renner sells nice sets of premade
> upright dampers about 2 1/4" or so long.  A bit pricey at $50/set.  Look
> inside a European upright and you will likely see a set if it is a Renner
> action.  We just make our own.  Make several sets at a time as a time
> saver.
>
> Dale Fox
>
> On Thu, 30 Aug 2001 15:21:25 -0400 "Farrell" <mfarrel2@tampabay.rr.com>
> writes:
> > Thanks for the input Ed. Yes, I was planning on getting enough
> > material for
> > 3 or 4 sets of dampers. I was also thinking of the mass thing. Bill
> > indicated he made his little damper 2-1/4" by 3/8" rectagles out of
> > basswood. I was thinking at least to start with some hard maple or
> > any other
> > dense wood that glues well just to put a little mass in the system.
> > I figure
> > it is not like the grand damper in that you are lifting it up - you
> > will
> > only have a small amount of inertia to overcome because the damper
> > travel
> > arc is nearly horizontal. I'll give some thought to the lead thing.
> > I think
> > I will avoid the fishing weights :-). The lead I have from the
> > Stanwood
> > stuff could simply be glued to the back (pianist side) of the
> > hardwood
> > damper rectangle is extra weight is proves beneficial - or maybe
> > even
> > wrapped around the dowel damper head and secured with a drop of
> > thick CA
> > glue. I'll keep the spring tension in mind also.  Thanks.
> >
> > Terry Farrell
> >
> > ----- Original Message -----
> > From: "Ed Sutton" <ed440@mindspring.com>
> > To: <pianotech@ptg.org>
> > Sent: Thursday, August 30, 2001 2:43 PM
> > Subject: Re: pianotech-digest V2001 #1106
> >
> >
> > > Terry-
> > > I have done this.  It is worth doing.  You may also need to
> > replace the
> > > damper wires and bend them to a different shape to get clearance
> > between
> > the
> > > wire and adjacent damper heads.
> > >
> > > Also add some small weights to the damper heads.  It will improve
> > damping
> > > and allow you to soften the springs in the tenor and treble, which
> > will
> > make
> > > the action lighter.  One way is to drill the old damper heads to
> > hold the
> > > little 1/4 inch leads from Apsco.  Another is to wrap lead wire or
> > clamp
> > > fishing weights around the damper wire.
> > >
> > > When you buy the supplies for the dampers, buy enough for 3 or 4
> > more
> > > pianos.  Those trips to the hobby shop waste time.
> > > Ed Sutton
> > >
> > >
> > > ----------
> > > >From: owner-pianotech-digest@ptg.org (pianotech-digest)
> > > >To: pianotech-digest@ptg.org
> > > >Subject: pianotech-digest V2001 #1106
> > > >Date: Thu, Aug 30, 2001, 10:53 AM
> > > >
> > >
> > > >
> > ---------------------------------------------------------------------
> > > >
> > > > Date: Thu, 30 Aug 2001 10:34:50 -0400
> > > > From: "Farrell" <mfarrel2@tampabay.rr.com>
> > > > Subject: Upright Damper Replacement
> > > >
> > > > Hi gang. Bill Spurlock wrote an article in the Journal in '94
> > about
> > upright
> > > > damper replacement. The bottom line was that he said that he
> > found that
> > many
> > > > or most old uprights had bass dampers that were too short and he
> > had the
> > > > best luck with dampers that were from 2 to 2-1/2 inches long,
> > equipped
> > with
> > > > three pieces of 5/8" long wedges. He described how he made his
> > own
> > dampers
> > > > (making the little boards and gluing the dampers onto new dowel
> > damper
> > > > heads) and the process he uses to determine what size will work
> > the best
> > for
> > > > any particular piano.
> > > >
> > > > Have any of you gone this route? Or know anyone that has? Is
> > this
> > generally
> > > > a good way to go about getting good working new dampers on an
> > old
> > upright? I
> > > > think most of what Bill Spurlock writes is pretty much right on
> > target,
> > but
> > > > just looking for a second opinion. This is my first upright
> > damper job,
> > so
> > > > it's not as if I gonna draw upon my own personal vast resources
> > of
> > > > experience. Thanks.
> > > >
> > > > Also, he does not mention using the dowel damper heads in the
> > tenor, but
> > > > does suggest that some of the first strings in the low tenor
> > often
> > benefit
> > > > from a longer damper. Can I trust that there is nothing wrong
> > with using
> > the
> > > > dowel damper heads in this area? And is there anything wrong
> > with making
> > > > your own dampers for all the treble strings (that originally had
> > dampers)
> > > > and mounting them on dowel damper heads? Thanks again!
> > > >
> > > > Terry Farrell
> > > >
> > > > ------------------------------
> >
>
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