Touchweight Metrology Question

[Mark Wisner]

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The spread on all Yamaha grands (so far, anyway) is 112.5mm.

Mark Wisner
Piano Service
Yamaha Corporation
mwisner@yamaha.com

>>> oleg-i@wanadoo.fr 05/15/02 11:58AM >>>
Hello,

Whould you please telle us what is the correct spread distance on the G
series ?
Any time I saw one (1970 piano) with extra heavy touch (and little =
keydeep),
the whippen rail had moved towards the front .

I thought of the DW UW figure of these pianos as to be around 52 g DW vs =
28g
UW env - is it correct ?)

Thanks.


Isaac OLEG

> -----Message d'origine-----
> De : owner-pianotech@ptg.org [mailto:owner-pianotech@ptg.org]De la part
> de Baldwin Yamaha Piano Centre
> Envoye : mercredi 15 mai 2002 18:51
> A : pianotech@ptg.org
> Objet : Re: Touchweight Metrology Question
>
>
>
> Hi Terry,
>                  Back to the original heavy touch. Balance rail hole
> fitting, has a huge effect on feel. Yamaha tends to have tight
> balance rail
> hole fitting.
> Two suggestions before you start. 1. Polish all key pins and coat with
> protech. 2.Fit the balance rail holes to the pin. Down in humid
> swamp land,
> there should be a big difference.
>
> Regards Roger
>
>
> At 08:02 AM 5/15/02 -0400, you wrote:
> >Richard wrote:
> >
> >"Basically what I do is to pick a SW curve based on the target ratio I
> >want,  install FW to fit the FW max table ...."
> >
> >How do you relate/figure SW to SWR? I thought target SW should
> be based on
> >piano tone, and then geometry and FW and whatever adjusted to accomodate=

> >the desired SW?
> >
> >Unfortunately, this piano appears to have new Yamaha hammers on it. But
> >they are not tapered, or arced. Friction in the hammer-shank flanges is
> >all over the place. Is it reasonable to try the water/alchohol thing to
> >shrink-size the bushings before repinning the whole shebang? I wish the
> >hammers and knuckles were more worn, then it would be easy to
> recommend a
> >new top half of the action.
> >
> >By installing FW to "fit" the FW max table, are you suggesting that FW
> >should be at or near that maximum value? If so, why? Doesn't
> "maximum" in
> >this case mean that "at that value or below is fine"? Or not? Thanks.
> >
> >Terry Farrell
> >
> >----- Original Message -----
> >From: "Richard Brekne" <richard.brekne@grieg.uib.no>
> >To: <pianotech@ptg.org>
> >Sent: Wednesday, May 15, 2002 3:11 AM
> >Subject: Re: Touchweight Metrology Question
> >
> >
> > > Farrell wrote:
> > >
> > > > I am taking my second stab at touchweight metrology analyses of an
> > action (my first was half-hearted and incomplete). Yamaha G5, 1963,
> > action in very good condition. Complaint: action heavy. It is
> indeed with
> > DWs all over the 60 to 80 gram range (mostly around 65 grams).
> Some notes
> > do have a lot of friction, but many measured notes only have 10, 11, =
12
> > grams friction, so clearly there is a problem with either too
> much weight
> > hanging out somewhere, or bad geometry. KR is 0.49, BWs are
> mostly around
> > 50 to 55 grams or so. I have not measured strike weights and wippen
> > radius weights yet.
> > >
> > > KR of 0.49 is down there quite a bit... which means the
> capstan is in a
> > good ways and you should be able to lift all kinds of weight, but need
> > lots of key dip to get things to work.  So if you are in addition
> > experiencing medium heavy to heavy DW then you probably have a
> fun job on
> > your hands.
> > >
> > > But this is real sketchy just with KR and vague DW, BW and
> Friction hints.
> > >
> > > I like to take a few (10-12) samples of all parameters to get an =
idea
> > of where the action is, then plan what I want to end up with a "least
> > work possible" perspective. I aggree with David that ending up around
> > 5.75 SWR is a good generic solution that seems to work well
> with most actions.
> > >
> > > Basically what I do is to pick a SW curve based on the target ratio =
I
> > want,  install FW to fit the FW max table David includes with his kit,
> > and adjust leverage as neccessary to make a decent enough fit.
> > >
> > > Make sure the action spread and friction issues are taken
> care of ahead
> > of time.
> > >
> > > > Maybe too early yet to even be asking questions. Just wondering if
> > anyone that is familiar with this process has any
> recommendations. Thanks.
> > >
> > > This proceedure makes for a decent generic solution, and gets you
> > started along the Stannwood path. It gets you looking at and using his
> > formula in a few different ways, and you start routines in his
> practical
> > methods. It doesnt allow for much "design" work tho as you are pretty
> > much stuck with a very narrow set of SW and FW parameters. But
> its a good
> > and easy place to start.
> > >
> > > In your case, if your KR is indeed only 0.49,  I would guess
> you might
> > end up moving the capstan line back a bit
> > >
> > > > Terry Farrell
> > > >
> > >
> > > Grin.. Ed will correct me if I am thinking backwards again. It gets
> > worse when I think upside down :)
> > >
> > >
> > > --
> > > Richard Brekne
> > > RPT, N.P.T.F.
> > > Bergen, Norway
> > > mailto:rbrekne@broadpark.no
> > > http://home.broadpark.no/~rbrekne/ricmain.html
> > >
> > >
>
>
>

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