Spring behavior

[gordon stelter]

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
> > _______________________________________________
> > pianotech list info:
> https://www.moypiano.com/resources/#archives
> >
> 
> _______________________________________________
> pianotech list info:
https://www.moypiano.com/resources/#archives


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