Violin Construction and Mechanics - Bow

Bow

The bow consists of a stick with a ribbon of horsehair strung between the tip and frog (or nut, or heel) at opposite ends. At the frog end, a screw adjuster tightens or loosens the hair. The frog may be decorated with two eyes made of shell, with or without surrounding metal rings. A flat slide usually made of ebony and shell covers the mortise where the hair is held by its wedge. A metal ferrule holds the hair-spreading wedge and the shell slide in place. Just forward of the frog, a leather grip or thumb cushion protects the stick and provides grip for the player's hand. Forward of the leather, a winding serves a similar purpose, as well as affecting the balance of the bow. The winding may be wire, silk, or whalebone (now imitated by alternating strips of yellow and black plastic.) Some student bows (particularly the ones made of solid fiberglass) substitute a plastic sleeve for grip and winding.

The stick is traditionally made of pernambuco or the less expensive brazilwood, although some student bows are made of fiberglass. Recent innovations have allowed carbon-fiber to be used as a material for the stick at all levels of craftsmanship. The hair of the bow traditionally comes from the tail of a white male horse, although some cheaper bows use synthetic fiber. The hair must be rubbed with rosin occasionally so that it will grip the strings and cause them to vibrate. Bow hair is regularly replaced when the ribbon becomes skimpy or unbalanced from hair breakage, or when the player feels the hair has "lost its grip."