Violin construction and mechanics

A violin consists of a body or corpus, a neck, a finger board, a bridge, a soundpost, four strings, and various fittings. The fittings are the tuning pegs, tailpiece and tailgut, endpin, possibly one or more fine tuners on the tailpiece, and usually a chinrest, either attached directly over the tailpiece or to the left of it.

The body of the violin is made of two arched plates fastened to a "garland" of ribs with animal hide glue. The ribs are what is commonly seen as the "sides" of the box. The rib garland includes a top block, four corner blocks (sometimes omitted in inexpensively mass-produced instruments,) a bottom block, and narrow strips called linings, which help solidify the curves of the ribs, and provide extra gluing surface for the plates. From the top or back, the body shows an "hourglass" shape formed by an upper bout and a lower bout. Two concave C-bouts between each side's corners form the waist of this figure, providing clearance for the bow.

The best woods, especially for the plates, have been seasoned for many years in large wedges, and the seasoning process continues indefinitely after the violin has been made. Glue joints of the instrument are held with hide glue, since other adhesives can be difficult or impossible to reverse when future repairs are in order. Parts attached with hide glue can be separated when needed by using heat and moisture, or by careful prying with a thin knife blade. A well-tended violin can outlive many generations of players, so it is wise to take a curatorial view when caring for a violin.

Typically the top (also known as the belly or table, in the U.K.) -- the instrument's soundboard) is made of quarter-sawn spruce, bookmatched at a strongly glued joint down the center, with two sound-holes (or "f-holes", from their resemblance to a stylized letter "f") precisely placed between the C-bouts and lower corners. The sound-holes affect the flex patterns of the top, or table, and allow the box to breathe as it vibrates. A decorative inlaid set of three narrow wooden strips, usually a light-colored strip surrounded by two dark strips, called purfling, runs around the edge of the top, and is said to give some resistance to cracks originating at the edge. It is also claimed to allow the top to flex more independently of the rib structure. Some instruments have two lines of purfling, or have knot-work type ornaments inlaid in the back. Painted-on faux purfling on the top is usually a sign of an inferior instrument. A slab-sawn bass bar fitted inside the top, running lengthwise under the bass foot of the bridge, gives added mass and rigidity to the top plate. Some cheaper mass-produced violins have an integral bass bar, carved from the same piece as the top. Ideally the top is glued to the ribs and linings with slightly diluted hide glue, to allow future removal with minimal damage.

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Wikipedia