Spurlock Damper Design

Dale R Fox foxpiano@juno.com
Fri, 31 Aug 2001 08:41:15 -0700


We use 3/32".  It is a multiply birch material.  Approximately 1/2" or
so,  three to a block.    We use our Spurlock felt cutting block as an
alignment jig.  Place the precut felt blocks at predetermined spots in
the "jig" and glue em up.

Dale F

On Fri, 31 Aug 2001 07:48:55 -0400 "Farrell" <mfarrel2@tampabay.rr.com>
writes:
> How thick an airplane ply do you use? How long do you make your felt
> segments? Bill Spurlock suggests 5/8" long, but that would occupy 
> 15/16" of
> the 20/16" -long damper board. You would only have a tad over 1/8" 
> between
> segments. Thanks
> 
> I think I will order a set of Yamaha dampers, a set of Renner 
> dampers, and
> make some of my own, and then decide what I want to do.
> 
> 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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