The cello is a complex instrument consisting of many different parts. Though the majority of it is composed of wood, some parts are made of steel, rubber, and metal.
Main Frame
The main frame of the cello is made from wood. Cellos are normally constructed with a spruce top. The back, sides, and neck are usually made of maple, although occasionally other woods such as poplar are used. The top and back are hand carved, although less expensive cellos frequently have a top and back made of a laminate, giving an inferior sound. The sides are made by steaming the wood and bending it around forms. The cello body has a wide top, narrow middle, and wide bottom, the bridge and f-holes in the middle.
Upper Neck
Above the main frame is the carved neck, which leads to a pegbox and then a scroll. The three are carved out of a single piece of wood. The pegbox consists of four tuning pegs, each which tunes its respective string by either tightening or loosening the string. Ebony is usually used for the tuning pegs, fingerboard, nut (piece above the fingerboard which the strings rest on), and tailpiece, but other dark woods can be used.
Boxwood or rosewood is sometimes used for the tailpiece, end pin, and/or tuning pegs. The tailpiece is also frequently made of metal. The bridge is not glued on; tension from the strings maintains it in place. The f-holes in the top serve two purposes: they allow sound to move from inside the instruments body out into the room, and provide access to the interior, for example to adjust the sound peg (see below). The instrument is supported by an endpin. Cellos are glued together using hide glue, which is strong yet also reversible, allowing for repair and restoration of the instrument should it need to be taken apart. Cellos can also be constructed from carbon fibre.
Internally, the cello has two important features: a bass bar, which is glued to the underside of the top of the instrument, and a round wooden sound peg (also called a sound post), which is sandwiched between the top and bottom. Like the bridge, the sound peg is not glued; Because of this, if it should be necessary to remove all of the strings, the cello must be kept horizontal, or the sound peg can fall over. A luthier has a special tool for positioning it should this occur.
Traditionally, bows are made from Pernambuco (high quality) or Brasil (lower quality) wood. Both woods come from the same species of tree (Caesalpina sappna L, or sappon wood, native in Asia), but Pernambuco is the heartwood of the tree and is much darker (Brasil wood is stained/painted dark to compensate).
Pernambuco is a heavy, resinous wood with great elasticity and high sound velocity which makes it an ideal wood for instrument bows. The hair is horsehair, though synthetic hair has become available nowadays. In addition, the bow can now also be made of fiberglass or carbon fibre (or wood with a carbon fibre core), serving as alternatives to the traditional wooden bow. The hair is coated with rosin (normally every time the instrument is played) to improve the grip on the strings. Bows need to be re-haired periodically as the hair loses its grip over time. The hair is kept under tension while playing by a screw which pulls the frog (the part of the bow one holds) back. Leaving the bow tightened for long periods of time can damage it, by warping the stick.
Baroque cellos differ from the modern instrument in several ways. The neck has a different form and angle which matches the baroque bass-bar and stringing. Modern cellos have a retractable metal (or sometimes carbon fibre) spike at the bottom to support the instrument (and transmit some of the sound through the floor), while Baroque cellos are held only by the knees of the player. Modern bows curve in and are held at the frog; Baroque bows curve out and are held closer to the bows point of balance. Modern strings normally have a metal core, although some use a synthetic core; Baroque strings are made of gut (the G and C strings sometimes wound with metal).
Modern cellos often have fine-tuners connecting the strings to the tailpiece, which make it much easier to tune the instrument — Baroque cellos do not use fine tuners. Baroque tuning is generally lower then standard tuning, usually A415 (equivalent to modern A-flat). Wolf Tone eliminators are sometimes placed on cello strings between the tailpiece and the bridge in order to eliminate Wolf Tone.
http://www.celloinfo.comoriginal article page