Bridge & Soundpost Veneers
by Joseph Curtin
Two of a violin’s most vulnerable areas are the points of contact between the soundpost and the inside of the top, and between the bridge feet and the outside of the top. In both cases, large forces are brought to bear on small areas of relatively fragile wood. Moving the soundpost to a slight angle from its point of true fit, as is commonly done during adjustments, tends to dent the inside of the top. The sliding motion itself, especially when done under full string pressure, can tear the grains of the spruce.
Soundpost damage to the inside of a violin top
The bridge feet create similar problems. When the top of the bridge gets pulled toward the fingerboard during tuning, the downward force of the strings gets concentrated at the front edge of the feet, causing them to dig into the top. The bridge is then rocked back by the player – often too far – and this rocking from edge to edge can lead to the indentations and cracks under the bridge feet seen in so many old instruments.
Bridge-foot damage to the top of a Guarneri del Gesu violin
The tops of my instruments are protected by hardwood veneers in the bridge-foot and soundpost areas. The soundpost veneer is roughly the size of a quarter. It is made from quarter-cut hard maple about 0.3 mm thick. The grain is rotated slightly with respect to the top-wood, thus providing additional resistance to cracking. Surprisingly, a soundpost veneer does not seem to affect the sound of an instrument, or require any change in the normal soundpost position.
I mark the “ideal” position of the soundpost in relation to the bridge by lines inscribed on the soundpost veneer. These lines serve as reference points, about which fine adjustments can be made. (Similar lines are marked in the corresponding position on the inside of the back.)
Veneer installed and marked with default soundpost position
Bridge-feet veneers consist of two small rectangles of hardwood – in this case, cherry. They are about 0.25 mm thick and about 1 mm larger all around than the bridge foot. The grain of the veneer runs parallel to that of the top. Once installed, a coat or two of varnish on top of the veneer helps prevent the bridge from moving out of place. I began installing soundpost veneers on my instruments in 1997. Bridge-feet veneers came a few years later. In the years since, both have proved remarkably effective in their protective functions.
Bridge-foot veneers on a violin top