Spring behavior

David Ilvedson ilvey@sbcglobal.net
Mon, 21 Oct 2002 16:29:53 -0700


Exactly!  That's why any grease in the rep groove is not
necessary or advised.  A dry lube, micro-fine teflon powder
etc. is the lube of choice...IMHO   One of the first things I do on a complete
regulation is flip the stack and clean out the grooves.

David I.



----- Original message ---------------------------------------->
From: Isaac OLEG <oleg-i@wanadoo.fr>
To: gordon stelter <lclgcnp@yahoo.com>, Pianotech Mailing list <pianotech@ptg.org>
Received: Tue, 22 Oct 2002 01:03:42 +0200
Subject: RE: Spring behavior

>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
>> > > _______________________________________________
>> > > pianotech list info:
>> > https://www.moypiano.com/resources/#archives
>> > >
>> >
>> > _______________________________________________
>> > pianotech list info:
>> https://www.moypiano.com/resources/#archives
>>
>>
>> __________________________________________________
>> Do you Yahoo!?
>> Y! Web Hosting - Let the expert host your web site
>> http://webhosting.yahoo.com/
>>

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


This PTG archive page provided courtesy of Moy Piano Service, LLC