David, I guess we don't aim for any large amount of defluxion in the struts, the plate is very brittle in this direction. We can consider it not to be moving (much) while wedging, magnetic bases and dial gauges are a must for this, they are not expensive. Bests 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 David Love > Envoye : vendredi 25 juillet 2003 22:09 > A : Ron Nossaman; Pianotech > Objet : Re: soundboardinstal again > > > Ron: > > I was basing my assumption on an article I read some years > back by Bob Hohf > (I think) about bridge recapping. He used a go bar method > for prestressing > the bridge prior to setting bearing. In wedging the board, > you are aiming > for a certain amount of deflection at each strut, right? > Wouldn't the > amount of pressure on the board based on the amount of > deflection vary > quite a bit based on the location of the struts and flex in > the struts, > among other things. Why would this be a more reliable > method (though, you > are right, I have not experimented with the go bar method). > BTW, what > would be "dangerous" about the use of go bars this way--I think you > mentioned that in a previous post. > > David Love > davidlovepianos@earthlink.net > > > > [Original Message] > > From: Ron Nossaman <RNossaman@cox.net> > > To: <davidlovepianos@earthlink.net>; Pianotech <pianotech@ptg.org> > > Date: 7/25/2003 10:22:29 AM > > Subject: Re: soundboardinstal again > > > > > > >I believe go bars can be calibrated based on thickness, > type of wood (ash > > >or hickory) and length. You have to have a way of > setting the piano at a > > >controlled height below a top deck. Then by using go > bars of a specific > > >length differential between the top of the bridge and > the top deck, and > the > > >go bar itself, the amount of force given by each go bar can be > determined. > > > > > > > > >David Love > > > > Don't just believe it, try it and find out. See if you > can pre-determine > > the final pressure from a bowed go bar pushing on a > deflecting soundboard > > when they reach equilibrium. You could be famous. > > > > Ron N > > > > _______________________________________________ > pianotech list info: https://www.moypiano.com/resources/#archives >
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