Touchweight Metrology Question

Farrell mfarrel2@tampabay.rr.com
Thu, 16 May 2002 12:48:30 -0400


I definately did not make that statement. I believe Richard Brekne said that. I'm the confoozed one! I will defer to Richard for an explanation.

Terry Farrell
  
----- Original Message ----- 
From: "Gordon Holley" <gholley@hi-techhousing.com>
To: <pianotech@ptg.org>
Sent: Thursday, May 16, 2002 10:32 AM
Subject: RE: Touchweight Metrology Question


> Hello Terry Farrell,  
> I've been following this discussion between you, Richard Brekne, 
> Roger and Isaac Oleg and I have a question regarding a comment you 
> have made in this discussion.  You write "I agree with David that 
> ending up around 5.75 SWR is a good generic solution that seems to 
> work well with most action."
> Are you combining the abbreviations for Strike Weight (SW) and Strike 
> Weight Ratio (R) into one (SWR).  I'm not making an issue, just 
> wanted to be sure of your usage.  This has been most interesting for 
> me as I'm studing this phase of regulation and working on my own 
> "Farrand" Grand.  
> And thank you all for your contributions to this PTG list.  If one 
> reads and studies all the comments and challenges, this list does 
> become a great lecture hall.
> So far in the past 18 months I've printed out over 16 reams of paper 
> on many subjects and am now filing into my third file drawer
> I really do appreciate this source of knowledge.  
> Respectfully, Gordon Holley, Goshen, Indiana
> 
> On 15 May 2002 at 13:43, Mark Wisner wrote:
> 
> > 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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