CARVING THE THROAT. The frog part 3.

To fit on the silver ferrule, a projection or tenon is cut into the ebony frog piece and this is shaped until the ferrule slides on tightly. Then the frog is brought down to the final height and length. The sides of the frog are scooped out with a gouge and then we are ready to start the ‘degorgement’ or throat. Like the head, the frog is a sculptural form defined by its function of holding a flattened band of hair a certain distance off the stick and sliding back to tension the hair as needed. Beyond that the frogs shape is defined by a combination of tradition and the desire of each maker to do something different, something a little different from the next maker. This is expressed most noticeably in the sculptural shape of the throat, the area between the ferrule and the thumb projection. The throat can be squared off and angular as in Persois’s bows or gently rounded as in Voirin’s or a combination of the two as in Peccatte’s.

The challenge of the throat’s design lies in the fact that the ferrule presents a steeply convex surface while the sides of the frog are hollowed out or concave. Then the thumb projection is steeply concave again so the throat’s shaping must gracefully traverse these opposing surfaces. In addition the continuation of the flanks of the frog into the throat can be abrupt or tapering inward to a small radius. So this simple shape bounded on three sides by the rest of the frog can manifest an almost infinite number of shapes that express the personalities behind them.

The throat is shaped with a knife and here as in the head we rely on tools that give us the measure of control we need. Once the shape is fully defined, some strokes of a needle file smooth it out and we are ready to go on. Now the frog looks complete except that there are no channels, mortise or pearl eyes and slide. The polishing will come later.

SILVER. The Frog part 2.

Bow making requires a number of techniques that a jeweler uses and that includes cutting and shaping silver or gold and joining them with solder. Normally we work with silver. Each nation has precious metal standards and England and the US have the Sterling system. France has had several standards over the last two centuries but for quite some time their silver has been called ‘argent premiere titre’ and it consists of 95% silver alloyed with 5% copper to harden it. Since Sterling silver has 92.5 % silver and 7.5% copper it has a slightly different luster than the French silver we use in this shop.

Gold commonly accompanies the finest work of a maker but this is not necessarily the case. All we have to do is look at the elegant silver mounted bows of the great makers Francois Tourte or Dominique Peccatte; it is often evident they went all-out to make a given bow, the stick is phenomenal. A silver bow may have been made for a great professional player who could not justify the expense of gold and indeed at the time gold mounted bows were likely destined for the nobility or the wealthy. It is also a fact that of all the precious materials in a great bow, gold is the most easily obtained. The gold is expensive but the stick is priceless. Gold also weighs more than silver; gold mountings will weigh about a gram more, which is sometimes an important consideration. But some contemporary makers consider a bow with gold mountings to be their highest grade so in this case purchasing gold mountings from them is well worth consideration.

After the rough frog piece has been prepared, we make the ‘passant’ or ferrule that contains and spreads the hair. According to Bernard Millant this ring was invented by Francois Tourte in 1782 or 1783 to accommodate the demands of Viotti and Kreutzer who were troubled with the hair bunching as they played at the frog. Prior to this time the frog was open with the hair coming out of a mortise in the same way it does from the head. A jeweler’s saw is used to cut out two pieces of silver, one of which is bent into an arch. Then they are heated to red-hot and soldered together to form a ring. This ‘D’ shaped ring is hammered out to shape and it is then filed to size. Now it’s ready to fit on the frog.