Pegs
At the scroll end, the strings ride over the nut into the pegbox, where they wind around the tuning pegs. Strings usually have a colored "silk" wrapping at both ends, for identification and to provide friction against the pegs. The peg shafts are shaved to a standard taper, their pegbox holes being reamed to the same taper, allowing the friction to be increased or decreased by the player applying appropriate pressure along the axis of the peg while turning it. Various brands of peg compound or peg dope help keep the pegs from sticking or slipping. Peg drops are marketed for slipping pegs. Pegs may be made of ebony, rosewood, boxwood, or other woods, either for reasons of economy or to minimize wear on the peg holes by using a softer wood for the pegs.
Attempts have been made to market violins with machine tuners but they have not been generally adopted, primarily because earlier designs required irreversible physical modification of the peg box, making violinists reluctant to fit them to classical instruments, and because they added weight at the scroll. Early examples included large geared pegs that required much larger holes and/or bracing bars and additional holes, and tuning machines resembling those on a double bass, with metal plates screwed to the sides of the pegbox. Recent advances in machining technology have allowed the creation of several types of internally geared heads that fit into the pegbox using friction and are the same size as classical pegs, requiring no more modification than would be seen in any peg replacement. These have gained popularity in recent years, although no specific design has become standard.
Read more about this topic: Violin Construction And Mechanics