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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