Today is that point where we cut holes in the front of the violin plate which we just spent 4 days making contoured, inlaid, smoothed, and very thin. We are going to draw intricately curved lines, drill four holes in the middle of the plate, cut between the holes with a jewelers fret saw, and use a free hand knife to carve squiggly lines between the holes. Any mis-step will render the painstaking work of the last 4 days a piece of firewood. Do you feel my nervousness? Today we mark and cut the f-holes, or sound holes.
The pattern of the f-holes must be laid out very precisely, there are little nicks on the inside edges that must be 195mm from the top edge of the violin. These nicks identify the location of the violin bridge, which defines the string length and ability for a violinist to play the correct note when a finger is placed on a particular spot along a string. The top holes must be 42mm apart, which defines the width of the bridge feet, and the position of the base bar running under the G string, the lowest note on the violin. Then the bottom hole must be exactly the same distance from the nick as the top hole, but larger, and in the opposite direction. For all these precise measurements you would think that makers would have standardized the f-holes with an exact shape over the past 400 years. Sorry, no such luck, the final shape of the f-holes is ‘artistic’ it shows the variation and style of a particular violin maker.
Once the f-holes are cut we can locate the position of the bass bar on the inside of the plate. The bass bar provides longitudinal strength to the thin spruce top connecting the top vibrating chamber with the bottom vibrating chamber. The violin bridge will exert around 105 pounds of downward pressure on the center of the top plate (which we just weakened by cutting holes), the bass bar will help support this weight and carry the vibrations on the lower, G string, side of the bridge. This 5.5 mm thin piece of wood is contoured exactly to the inside plate. We used chalk on the plate and rubbed the wood against the chalk, then carefully (redundant word in violin making) filed the chalky high points off the bass bar until there was even chalk on the whole complex curve of the bass bar.