Hello Roger, I like a bit of clearing on the bedding aurally too, I listen for knock on the front rail, pushing on it with my thumb to compare the noise, I understand we can listen to an open or too compressed balance rail, but I am not sure I understand when you say that you aim for the same tone - You mean the same tone all along each rail, or a tone that tells the quality of the weight on the frame ? Or is it to be done without the keys ? I've been a long time confusing knocks that came from the back rail, very often when the regulating screws are screwed a lot, and the knocking of a correctly bedded balance rail (that knocks evenly and easily even if there is a lot of pressure, assuming it is evenly distributed. Are the intermediate screws (hidden) checked for knocking in the same "tone" idea ? thanks and Best regards. Isaac OLEG Isaac OLEG Entretien et reparation de pianos. PianoTech 17 rue de Choisy 94400 VITRY sur SEINE FRANCE tel : 033 01 47 18 06 98 fax : 033 01 47 18 06 90 cell: 06 60 42 58 77 > -----Message d'origine----- > De : pianotech-bounces@ptg.org > [mailto:pianotech-bounces@ptg.org]De la > part de Roger Jolly > Envoye : vendredi 23 mai 2003 02:52 > A : Pianotech > Objet : Re: No Power Yamaha revisited > > > > > Hi Avery & Ric, > I have a good minds eye view, of > what is going > on, but I'm not so sure I can explain it well. But here > goes. (Send me a > deluxe flame suit Conrad). > > If you have the bolts just touching, there is no > compression force acting > on the balance rail. With rapid forceful playing, there is > a small amount > of bounce taking place at the balance rail, robbing the > action of a lot of > energy. It gets dissipated within the frame. > Jack the bolts a little further down, you start to bow the cross > struts. and putting some compression into the rail. , and > firmly seating > it to the bed. At the Yamaha Technical Academy, they > spend a good deal of > time teaching you how to tune these rails in aurally. > takes more than a > little practice to get optimum results. > The front rail is done first, by tapping on the front rail > with a kind of > 45 degree blow, to the leading edge of the rail. (You can > hear better than > the traditional method of holding a key down and thumping > on the key, the > front rail punching absorbs a lot of noise,) Then the bolts > are adjusted so > the front rail just starts to lift, then back off about 1/4 > turn. Next > step is get all the glides bedded so the tone is the same > when lifting up > on the hammer rail, and thumping down on the balance rail. > > The closest analogy I can think of, is like string bearing > across the > bridge. Too much bearing and a loss of tone, too little > loss of tone. > > Now I will crawl under my rock and smile. > > Regards Roger > > PS I thought we covered the topic of hardwood and softwood > rails, quite > well in the Interactive Grand Regulation series. Gee that > was 2 years > ago. Tempus fugit. > > > At 04:03 PM 5/22/2003 -0500, you wrote: > >Hi Roger, > > > >But why won't Yamaha tell us how they do it? (See my > previous post to > >Richard.) > > > >Avery > > > >At 01:56 PM 05/22/03 -0600, you wrote: > >>Hi Ric, > >> A very soft flexible action frame, they move > a lot. I bed > >> these frames every time I tune a Yamaha grand. > >>With practice it only takes about 3 or 4 minutes. The > weight of the keys > >>is more than enough to flex those frames, hence the change in dip. > >>The design is such that the frame is is supposed to flex. > >>Bin thar and bought the tee shirt. <G> > >> > >>Regards Roger > >> > >>At 06:12 PM 5/22/2003 +0200, you wrote: > >>>Ok guys and gals... > >>> > >>>I gots to eat crow here... I think anyways. As it turns > out I managed > >>>to finnally solve the hammers bouncing all over the > place thing by > >>>turning up all the bed screws so that the key frame was > solidly bedded > >>>with the actuall wood of the balance rail a full 2 mm > elevated over the > >>>key bed. Huge increase in power, but this also caused an > increase in > >>>keydip to 10.5 mm (!) and forced a drop in blow to just above the > >>>cushions... perhaps the shanks are about 2-3 mm off. However.... > >>>absolutly no bouncing of neighboring hammers any more, > and that feeling > >>>of loosing power is gone. > >>> > >>>What I dont get is why the Balance Rail needs to be > elevated so much. > >>>And how are we supposed to determine the proper balance > rail height to > >>>begin with ? I was always told that glide bolts need to just make > >>>contact with the key bed... not to lift the whole darn > middle of the key > >>>frame up. > >>> > >>>Explainations please ? > >>> > >>>RicB > >>> > >>>-- > >>>Richard Brekne > >>>RPT, N.P.T.F. > >>>UiB, Bergen, Norway > >>>mailto:rbrekne@broadpark.no > >>>http://home.broadpark.no/~rbrekne/ricmain.html > >>>http://www.hf.uib.no/grieg/personer/cv_RB.html > >>> > >>> > >>>_______________________________________________ > >>>pianotech list info: > https://www.moypiano.com/resources/#archives > >> > >> > >>_______________________________________________ > >>pianotech list info: https://www.moypiano.com/resources/#archives > > > >_______________________________________________ > >pianotech list info: https://www.moypiano.com/resources/#archives > > > _______________________________________________ > pianotech list info: https://www.moypiano.com/resources/#archives >
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