Setting Bearing

I continue to work on two projects simultaneously, that being the Baldwin F and the Mason and Hamlin BB. Setting the bearing (determining how much down bearing will be exerted on the bridge surface)is one of the most demanding jobs, as you only get one chance to get it right (although there are ways to fudge it if you aren't satisfied with the final results). How much bearing is needed at various points on the bridge is determined by each rebuilders experience and theory as to what contributes to the tone quality desired. Every rebuilder has his own formula. A simplified explanation of the formula that I follow is that I determine to approximate the amount of downbearing to equal the amount of crown that is present in the soundboard directly below the area of the bridge where the bearing is being set.

The new bridge caps were installed at a thickness greater than necessary. The bearing is set by cutting notches in the cap to the desired finish height of the bridge cap, and then planing the wood surface to that height (thickness) determined by the notch.

To accomplish this, the bridges are dry fit to the soundboard and the soundboard is dry fit to the piano. The plate is then installed on the pinblock and set to it's predetermined height. A string is stretched between the agraffe or V bar and the bearing point on the plate at the rear of the bridge. The bearing on the bridge is determined by the amount of deflection on the string between the front and rear termination points.