Spring behavior

[Isaac OLEG]

Thanks for the acid info.

I've seen the use of more elaborated greases, as cork grease, in lieu
of mutton tallow.

Anyway after a little dust have been mixed with the grease, the
benefit is gone, and friction begin to be felt too much.

Isaac OLEG

> -----Message d'origine-----
> De : gordon stelter [mailto:lclgcnp@yahoo.com]
> Envoye : lundi 21 octobre 2002 15:08
> A : oleg-i@wanadoo.fr; Pianotech
> Objet : RE: Spring behavior
>
>
> Tallow and mutton fats are highly acidic and conducive
> to causing corrosion (bronze rep springs) Better to
> use Protek and Molybdenum lubricant.
>      Thump
> --- Isaac OLEG <oleg-i@wanadoo.fr> wrote:
> > Hello,
> >
> > Good points about the repetition speed , my theory
> > have some lead in
> > the wings (translated from French , may be shot in
> > the feet is OK ?).
> >
> > My thought was that the graphite grease in the
> > springs slot, as well
> > as the mutton tallow that is used on the key pins in
> > some factories,
> > can well be the artifacts that helps to even the
> > action feel, or act
> > as a security towards repetition, while not allowing
> > to repeat so fast
> > than in optimum configuration.
> >
> > For sure they slow things in the 2 cases, but the
> > final feel is then
> > more even, despite the irregularities in pinning ,
> > BW, and differences
> > in ratio from note to note.
> >
> > I had the bad surprise on some actions after
> > cleaning of the slot and
> > the spring, to be obliged to re pin more than
> > expected to obtain a
> > more even touch.
> > Sure the springs are too strong immediately when we
> > clean the
> > graphite, but the jack's return will be less fast,
> > as you point out,
> > with a less strong spring.
> >
> > The slowliness in the balance lever induced by the
> > spring add a delay
> > that allows to be sure that the jack/roller contact
> > is more secure,
> > because more tension goes towards the jack.
> >
> > For sure a very objectionable reason & method.
> >
> > For the key pins in particular, I always clean them,
> > and use only
> > Teflon actually but I believe the little grease that
> > stay at the
> > balance hole helps to maintain the key in place when
> > the hole is
> > almost pulley, that is why this mutton tallow is so
> > much used actually
> > in repairs.
> >
> > Regards.
> >
> > Isaac OLEG
> >
> >
> >
> >
> >
> >
> > is in place first
> >
> > > -----Message d'origine-----
> > > De : pianotech-bounces@ptg.org
> > > [mailto:pianotech-bounces@ptg.org]De la
> > > part de A440A@aol.com
> > > Envoye : lundi 21 octobre 2002 12:13
> > > A : pianotech@ptg.org
> > > Objet : Spring behaviour
> > >
> > >
> > > Oleg writes:
> > >
> > > >I used to worry about the graphite gunk in the
> > balancier
> > > slot, but have
> > > >find it to act as a regulator of the spring
> > tension,
> > > anyway when not too old.
> > > >As it slows the top of the lever it eventually
> > send more
> > > energy towards the
> > > >key , thus helping more repetition that a very
> > slippery
> > > spring that will tend
> > > >to push up the hammer too fast.
> > > >Any idea about it?
> > >
> > > Greetings,
> > >    I don't believe that the increased friction at
> > the top
> > > of the spring will
> > > increase repetition speed.  Under fast repetition,
> > the
> > > hammer doesn't rise
> > > from check before the jack is reset.  Rather, the
> > spring
> > > uses the inertia of
> > > the hammer to increase the speed of the key
> > return.  This
> > > necessitates that
> > > the spring move in the slot,(called the grub at
> > the
> > > factory), and any
> > > friction here will reduce the speed of the
> > spring's work.
> > >    As friction increases at the grub, the spring
> > may be
> > > strengthened to
> > > compensate, which may put more pressure on the
> > jack to
> > > return, but the spring
> > > doesn't lift the hammer in the time it takes the
> > key to
> > > rise far enough to
> > > allow the jack to reset. (try it,  put a hammer
> > into check
> > > and let go of the
> > > key as rapidly as possible, you will see the
> > hammer drop to
> > > rest without
> > > moving upwards at all. )
> > >    Also, the difference in key return speed
> > between a
> > > spring that slowly
> > > lifts the hammer and one that throws the hammer
> > off the
> > > jack is virtually
> > > nil.  There is no need for a spring to be strong
> > enough to
> > > feel the recoil in
> > > the key upon the hammer's release from check.  An
> > overly
> > > strong spring just
> > > creates wasteful resistance to fine escapment
> > control at
> > > pianissimo levels of
> > > play. It may force the drop to be set too low,
> > creating
> > > even more resistance
> > > during final escapement. It will also create
> > problems with
> > > checking, and a
> > > hammer that isn't checked will cause a much slower
> > key
> > > return than one that
> > > is.
> > > Regards,
> > > Ed Foote RPT
> > > _______________________________________________
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> > https://www.moypiano.com/resources/#archives
> > >
> >
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