Hello, R(Action ratio) is the global leverage of an action. It goes as R= 5 (too good leverage) to R = 7 and more. The term SWR (Strike Weight Ratio) means only that the leverage was assessed by the weight method developed by David Stanwood. Measuring the length of the different levers in the action can be used too, but in this case the term SWeight R is less appropriate, of course, but that mean the something : An action with a low Ratio (or SWR) will allow the use of a heavier hammer but will need more key deep or less blow distance. An action with a high ratio will throw up the hammer quickly, but the hammer may be lighter, key deep will be smaller too. With a compressed spread action (the whippen rail have move a little towards the front) , the ratio is higher, and you feel a too heavy hammer (and more friction than expected) . Some actions are more prone to this than others , due to the floating position of the whippen rail. When well finished, the rail may be locked in place with wood shims glued, as a safety mesure. Hope that helps. Regards to anyone. Isaac OLEG > -----Message d'origine----- > De : owner-pianotech@ptg.org [mailto:owner-pianotech@ptg.org]De la part > de Gordon Holley > Envoye : jeudi 16 mai 2002 20:15 > A : pianotech@ptg.org > Objet : Re: Touchweight Metrology Question > > > Hi Terry. Well, trying to follow this 4 page conversation was little > confusing and before jumping in on this subject with my question on > Strike Weight (SW) and Strike Weight Ratio (R) and the request for > some clarification on what (SWR) was, I did go to David Stanwoods > publication on the Touchweight Metrology where he writes in his > Glossary of terms and abbreviations: Strike Weight (SW) and Strike > Weight Ratio (R). > Now Newton writes "that most of the information is in the archives > written by David Standwood and attending a class on touch weight > metrology will clear up the rest". And then uses the abbreviation > (SRW) for Strike Weight Ratio. Now I'll join you in the ranks of > confusion and crawl back into my hole. Gordon > > On 16 May 2002 at 12:48, Farrell wrote: > > > 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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