I have been tapping the bridge pins themselves and not the string lately. The vibration will seat the string and won't damage the bridge top. Give it a try... David Ilvedson, RPT Pacifica, CA > From: "Richard Moody" <remoody@easnet.net> > To: <pianotech@ptg.org> > Subject: Re: tuning stability > Date: Mon, 11 May 1998 00:57:38 -0500 > Reply-to: pianotech@ptg.org > Here is another take on not about seating strings so much, rather as how > bearing affects the seating of strings. > Bearing is how much the strings push down on the bridge. To accomplish > this think of how much the bridge should push UP on the strings. The > string without a bridge would occupy a straight line from the hitch pin to > the upper bearing point. In order for the string to be amplified through > a soundboard, a bridge is needed. this bridge forces the string away from > its straight line so that contact can take place. > Now in most stringed instruments the point of contact of the bridge with > the string is just that..a point. In a piano however, there are TWO > points of contact with the bridge. This can be refered to as the front > bearing and the rear bearing on the bridge. This can be visualized by > imagining how the bridge surface between the front and rear bridge pins > contacts the string. Now you can see if this contact is not ideal, tapping > the string to make contact can only be temporary. > How can the contact not be "perfect"? Imagine the bridge rising to meet > the string as an elevator. There is the shorter string segment from the > rear of the bridge and the longer segment from the front of the bridge. > What then is the ideal plane of the bridge surface to the angle of > deflection of the string? If this "ideal" relationship has been met by > the piano maker, no tapping is necessary. The pressure of the string on > the bridge will seat the string properly. If the surface of the bridge is > canted away from the string, too far either way, you will be tapping > forever, in order to "seat the string" in order to reduce false beats or > tuning instability. > Even if the string is seated "properly", there is a debate about whether > more down bearing should be at the rear of the bridge or at the front of > the bridge. And engineers who argue that this is impossible to worry > about, (measure) because the tolerences are too small. But don't tell that > to the people who favor rear duplex systems, or the "accujust" hitch pin. > And there is also the concept that induced strain on a sound board > "amplifies" the sound.... > > In regards to tapping strings to the bridge with a hammer shank or brass > rod, I prefer a toothbrush handle. It seems to give a better sonic > response, in additon to the concerns mentioned below by N Barret, and R > Jolly. I have done this so rarely, because of considerations mentioned > above, I wonder if others might want to comment about the sonic > differences between wood, brass, or plastic tappers? > Richard Moody > 4-11-98 > ---------- > > From: Norman Barrett <barre46@ibm.net> > > To: pianotech@ptg.org > > Subject: Re: tuning stability > > Date: Sunday, May 10, 1998 10:41 PM > > > > Hello list, > > Let me post my 2 cents worth about seating the strings. The tool that I > made to > > do this job is a piece of 1/4" brass rod about 5" long. One end I have > filed a > > grove in to help keep it on the string. This tool fits nicely in the > > combination handle and I can just lightly bump each string down with the > heel > > of my hand. You could probably do the job by simply pushing down gently > because > > the only thing holding the string off the bridge is friction against the > bridge > > pin. This is my humble opinion. > > Norm Barrett > > > > Roger Jolly wrote: > > > > > Hi Jerry, > > > The reason I prefer a hammer shank, is that it will split > before > > > you can kink the wire, ( another scorce of false beats) also less > chance of > > > indenting the bridge. > > > > > >
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