Bridgetop Extravaganza Revisited

[Joe And Penny Goss]

Hi Terry,
I believe that Jon is refering to a very slight bump at the termination
points caused by the stiffness of the wire resisting going in a straight
line to the next point.
My idea is to work from the hitch pin to tuning pin, checking pitch drop,
and tuning if the pitch drops below 15 cents of where it should be.
On new string it usually is, seat the hitch pin and bridge pins bottom then
top, tune.
Then capo or agraff and pressure bar, tune. and lastly tuning pin coil, and
tune.
Wait for a week for the wire to stretch and
re tune. I do not use the wire wheel that I inherieted as I feel it causes
damage to the bridge cap.
Joe Goss
imatunr@srvinet.com
www.mothergoosetools.com
----- Original Message -----
From: "Farrell" <mfarrel2@tampabay.rr.com>
To: "Pianotech" <pianotech@ptg.org>
Sent: Wednesday, December 18, 2002 5:23 AM
Subject: Re: Bridgetop Extravaganza Revisited


> Hello Jon. JPG me, please. Exactly what natural curve are you trying to
remove?
>
> Terry Farrell
>
> ----- Original Message -----
> From: "Jon Page" <jonpage@attbi.com>
> To: "Pianotech" <pianotech@ptg.org>
> Sent: Wednesday, December 18, 2002 7:18 AM
> Subject: Re: Bridgetop Extravaganza Revisited
>
>
> > I wouldn't trust a shallow fill of epoxy to resurface the cap, recap.
> >
> > As far as pounding the string, I agree that it is over-rated and have
> > tapped the bridge pins as Roger Jolly suggested to relieve false beats.
> > I also devised a tool for removing the natural curve from the wire at
the pins
> > to improve the termination. I posted to the list a few years ago about
it,
> > I have a jpg file if any one is interested in viewing it.
> >
> > Regards,
> >
> > Jon Page
> >
> > At 02:13 AM 12/18/2002 -0800, you wrote:
> > >     Hi All,
> > >Just joined,  first post to this or any other group.  Serendipitous
> > >timing, just read all the recent bridgetop/ bridgepin posts.  Have a
1985
> > >Stwy D in the shop for action overhaul and restring.  I thought I was
> > >noticeing something funny about the bridges but was in denial until I
> > >started taking all the teardown notes.  The plain wire strings have
been
> > >pounded (seated) into the bridge so that at the edges there is more
wire
> > >diameter below the bridge top than above it.  When viewed from the side
> > >the wire makes a pronounced curve up onto the bridge and down again out
> > >the rear making accurate component readings impossible to do from on
top
> > >of the wire.  It was showing negative front bearing until I realized
what
> > >was happening and started using the actual bridgetop as
> > >reference.  Situation is most severe at capo sections and diminishes
down
> > >to what looks like normal grooves to me under the bass
> > >strings.  Deflection in strung piano is .5 deg at bottom of low
> > >capo,  1-1.5 deg rest of capo sweeping up to 2.5 deg at note 88.  There
is
> > >.250" crown at low capo.  (measured from top of board)
> > >     Is it possible this condition is due to the quality of the capping
> > > material?   I usually work on much older instruments.  I have never
seen
> > > string cuts like this.  Also the various pressures have caused dead
wood
> > > to swell up and check here and there around the terminations.  Again
I'm
> > > not used to seeing this.  Inspection of the pins under magnification
> > > shows the string resided in two distinct locations.   My theory:  Pre-
> > > and Post Pounding.  There are also a lot of unexplainable nicks on the
> > > side of the pins.  The pins pull out easily.  No cracks to speak
> > > of.  This is an institutional piano which has probably been in
Southern
> > > California its whole life.
> > >     What I'm thinking about doing is similar to what Dale Erwin just
> > > posted.  I've never done the epoxy bridge thing but I'm familiar with
the
> > > nasty stuff. I'm imagining thickening it enough with colloidal silica
so
> > > it won't run down the notches or too much into the holes and applying
it
> > > with a small spatula.  I want to fill those deep grooves (at least on
the
> > > speaking side) and then sand the top flat.  If I put the stuff on in
the
> > > morning can I pare/renotch and redrill at the end of the day before it
> > > gets too hard and while I can still find the original holes?
> > >     Looking forward to peoples responses.
> > >
> > >     I want to stop using the misnomer "string seating" in favor of
wire
> > > straightening (or something similar)  which is what I do at a low
lateral
> > > angle (around the bridges anyway).  I have never been convinced of the
> > > need of downward tapping pressure at the bridges.  For some reason
this
> > > is one of the first things new technicians are taught and the thought
of
> > > them going around with little hammers and pounding on pianos scares
> > > me.  We straighten wire for control of damper and hammer contact and
for
> > > quick stabilization of new strings.  Perhaps having the wire come
> > > straight out of the bridge helps the string to vibrate in a more
> > > perpendicular plane even.  I don't really know.  After you take a few
> > > pianos apart you find that even in a negative bearing situation the
> > > angled pins hold the string tight to the bridge.  If there is so much
> > > negative bearing that they don't then no amount of pounding will hold
> > > them there.  But I guess that is another thread.   Right now I need
help
> > > getting out of this mess.  I have finally accepted I have to pull the
> > > plate.  So much for the quick restring of a fairly new instrument.
> > >
> > >Thanks,  Steve Bellieu
> >
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