SWR strike weight ratio is synomous with R, a shorter abbreviation. SW, strike weight, represents the weight of the hammer plus the shank, R (or SWR) represents the total action leverage. David Love ----- Original Message ----- From: "Gordon Holley" <gholley@hi-techhousing.com> To: <pianotech@ptg.org> Sent: May 16, 2002 7:32 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 > > > > > > > > > > > > > > > > > > > > > > > >
This PTG archive page provided courtesy of Moy Piano Service, LLC