The parts of the fiddle bow
The fiddle bow is essentially a long curved stick with some hair strung between both ends of the stick and held under tension. The bow is held at the frog end. The other end of the bow is referred to as the tip.
The frog end of the bow
The stick is generally made of wood (often pernambuco), although it is now also common to find bows made from carbon fibre. Some very cheap bows have a stick made of hollow plastic.
The stick is curved, and it’s structure is an important part of the mechanism for being able to tension the bow hair.
The bow is held in the bowing hand at the frog end. The frog itself encloses the mechanism that is used to tighten the hair on the stick. Its height and weight help to keep the bow balanced.
The lapping (also called the winding) creates a grip for the bowing hand on the bow’s stick. It is sometimes also referred to as the grip. It starts just in front of the frog and surrounds about 3 inches of the bow stick . The lapping is usually silver wire, wound in around the stick. The part of the winding nearest the frog is covered with leather to protect the spot where the player’s thumb sits.
The screw is used to stretch the bow hairs. As they are stretched they come under tension, and this tension begins to flatten out the curve of the bow stick. The screw should only be tightened enough to create a gap about the thickness of a pencil between the bow hairs and the stick, in the middle of the length of the bow.
It’s important to always loosen off the screw after you’ve finished playing, so the stick isn’t stored under continuous tension.
The hair used for a bow is generally horse hair. The surface of the horse hair has tiny scales on it. When you rosin your bow, tiny fragments of the rosin break off and lodge under the scales. Rosin is a slightly sticky substance. Its presence on the bow creates some friction between itself and the fiddle string. As the bow is pulled across a string, the string will initially stick to the bow hair because of the rosin. At some point the pull on the bow overcomes this friction, and as the bow continues to pull, the string loosens from the hair and moves in the opposite direction. The movement this sets up in the string is the first step to creating a note from the fiddle. So it’s vitally important you have rosin on your bow (without it, the fiddle would be completely silent!). It’s also important to have your bow rehaired from time to time, as the scales on the horsehair will get damaged an broken over time as you play.