Rabu, 20 Oktober 2010

Billiard table

A billiard table or billiards table (or more specifically a pool table or snooker table) is a bounded table on which billiards-type games (cue sports) are played. In the modern era, all billiards tables, regardless of whether for carom billiards, pool or snooker, provide a flat surface usually made of quarried slate, that is covered with cloth and surrounded by vulcanized rubber cushions, with the whole elevated above the floor.[1] An obsolete term is billiard board, used in the 16th and 17th centuries.[2][3]

Contents

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  • 1 History
  • 2 Parts and equipment
  • 3 Carom billiards tables
  • 4 Pool (pocket billiards) tables
  • 5 British Standard Pool (Billiards) Tables
  • 6 Snooker tables
  • 7 Other billiard tables
  • 8 References
  • History

    The earliest known billiard table, in the royal court of Louis XI of France (1461–1483),[2] was simply lawn brought indoors and placed on a large, everyday table. Rail-bounded, cloth-covered tables specifically for billiards, with wooden beds rail cushions (made of layered felt,[2] or stuffed with straw[citation needed]), soon evolved as the game's popularity spread among French and later other European aristocrats.
    The increasing demand for tables and other equipment in Europe was initially met by furniture makers of the era, some of whom began to specialize in billiard tables. By 1840, the table beds were made of slate, as they are to this day in quality tables. English table maker John Thurston was instrumental in this change, having tested the surface since 1826. After experimenting with hair, shredded fabric and feathers as stuffing for the cushions, he also introduced rubber cushions in 1835. This was not initially a success, as the elasticity of rubber varies with ambient temperature. After attempting to market cushion warmers with only partial success, Thurston was saved by the 1843 discovery of vulcanization by English engineer Thomas Hancock. Thurston used vulcanized rubber in his later cushions, and it is still used today by many manufacturers (some use synthetic materials). Thurston's first set was presented to Queen Victoria.[2]
    In the United States, manufacture of billiard tables has been ongoing since at least the mid-19th century. The forerunner of the Brunswick Company began commercial manufacture in 1845.[4] In San Francisco, California, several manufacturers were active by the late 19th century.[clarification needed]

    Parts and equipment

    Cushions

    Cushions (also sometimes called "rail cushions", "cushion rubber", or rarely "bumpers") are located on the inner sides of a table's wooden rails. There are several different materials and design philosophies associated with cushion rubber. The cushions are made from an elastic material such as vulcanized (gum or synthetic) rubber. The chiefly American jargon "rails" more properly applies to the wooded outer segments of the table to which the cushions are affixed.
    The purpose of the cushion rubber is to cause the billiard balls to rebound off the rubber while minimizing the loss of kinetic energy.
    When installed properly the distance from the nose of the cushion to the covered slate surface is 1 7/16" [1] while using a regulation 2 1/4" ball set.
    The profile of the rail cushion, which is the cushion's angle in relation to the bed of the table, varies between table types. The standard on American pool tables is the K-66 profile, which as defined by the BCA has a base of 1-3/16 inches and a nose height of 1 inch [2]. This[clarification needed] causes the balls' rebound to be somewhat predictable during game play.
    On a carom table, the K-55 profile is used (with a somewhat sharper angle than pool cushions). K-55 cushions have cloth, usually canvas, vulcanized into the top of the rubber to adjust rebound accuracy and speed [3].
    Finally, snooker tables may use an L-shaped profile, such as the L77 profile [4]. This is mostly[clarification needed] because snooker uses balls of a smaller diameter and smaller pocket entrances than pool does

    Cloth

    Billiard cloth (sometimes erroneously called felt) is a specific type of cloth that covers the top of the table's "playing area". Both the rails and slate beds are covered with 21–24 ounce billiard cloth (although some less expensive 19oz cloths are available) which is most often green in color (representing the grass of the original lawn games that billiards evolved from), and consists of either a woven wool or wool/nylon blend called baize.
    Most bar tables, which get lots of play, use the slower, thicker blended cloth because it can better withstand heavy usage. This type of cloth is called a woolen cloth. By contrast, high quality pool cloth is usually made of a napless weave such as worsted wool, which gives a much faster roll to the balls. This "speed" of the cloth affects the amounts of swerve and deflection of the balls, among other aspects of game finesse. Snooker cloth traditionally has a directional nap, upon which the balls behave differently when rolling against vs. toward the direction of the nap.

    Carom billiards tables

    Dimensions

    Regulation carom billiards tables are rectangles. The playing surface (measured between the noses of the cushions) is 2.84 meters by 1.42 meters with a 5 millimeter allowance.[5] The height of the table, measured from the playing surface to the ground is between 75 and 80 centimeters.

    [edit] The bed

    The slate bed of a carom billiard table must have a minimum thickness of 45 millimeters and is often heated to about 5 degrees C (9 deg F) above room temperature, which helps to keep moisture out of the cloth to aid the balls rolling and rebounding in a consistent manner, and generally makes a table play faster. A heated table is required under international carom rules and is an especially important requirement for the games of three-cushion billiards and artistic billiards.[1]
    Heating table beds is an old practice. Queen Victoria of England (1819–1901) had a billard table that was heated using zinc tubes, although the aim at that time was chiefly to keep the then-used ivory balls from warping. The first use of electric heating was for an 18.2 balkline tournament held in December 1927 between Welker Cochran and Jacob Schaefer, Jr. The New York Times announced it with fanfare: "For the first time in the history of world's championship balkline billiards a heated table will be used..."[1][6]

    Pool (pocket billiards) tables

    A cue ball and the 1 ball close to a pocket
    Pool tables, sometimes called pocket billiards tables, are specific to the various pool games such as eight-ball, nine-ball, straight pool and one-pocket. As the name implies, pocket billiards tables have pockets; normally six of them – one at each corner of the table (corner pockets) and one at the midpoint of each of the longer sides (side pockets).

    Dimensions

    Pocket billiard tables come in different sizes, typically referred to as 9-foot, 8-foot, or 7-foot tables. In all cases, the playing surface (the dimensions between the noses of the cushions) is rectangular with a 2:1 ratio. For a 9-foot table, the playing surface measures 100 inches by 50 inches (254 cm × 127 cm) with a 1/8 inches (3.175 mm) margin of error for either dimension. For an 8-foot table, the playing surface measures 92 inches by 46 inches (233.68 cm × 116.84 cm), again with a 1/8th of an inch margin of error for either dimension. These are the only two sizes authorized for tournament play by the World Pool-Billiard Association (WPA).[7] The playing surface for a 7-foot table is 76 inches by 38 inches (193.04 cm × 96.52 cm).

    Pockets

    Pockets, usually rimmed with leather or plastic, may have leather bags to catch the balls, common in home billiard rooms and pool halls, or (most commonly in the coin-operated tables found regularly in bars/pubs) may lead to ball-return troughs inside the table, which channel the balls into a collection chamber on one side of the table (or, in non-coin-op models, on the racking end of the table).

    The bed

    For World Pool-Billiard Association (WPA) tournament play, the bed of the pocket billiard table must be made of slate no less than 1 inch (2.54 cm) thick. The flatness of the table must be no greater than +0.020 inches (0.508 mm) lengthwise and +0.010 inches (0.254 mm) across the width.[7]
    Tables not for tournament play may often use a slate bed as well, but the slate may be less than 1 inch (2.54 cm) thick. Other materials used for pocket billiard table beds include wood (typically medium-density fiberboard) and synthetic materials under various trade names.

    Markings

    Sights, or diamonds, are put on the rails to aid in the aiming of bank or kick shots. There are six along each long rail (with the side pocket interfering with where the seventh one would go) and three along each short rail. These divide the playing surface into equal squares.
    Spots are often used to mark the head and foot spots. Other markings may be a line drawn across the head string and the outline of the rack behind the foot spot where the balls are racked. In addition, in artistic pool, lines are drawn between opposite sights putting a grid on the playing surface

    British Standard Pool (Billiards) Tables

    British Pool Table
    A British standard pool table, showing a cue ball and a red/yellow ball close to the (smaller) pocket.
    In the UK as well as a number of other countries, the standard pool table configuration is a little different from the American Pool table

    Dimensions

    British pool tables come in 6 ft x 3 ft or 7 ft x 4 ft varieties,[8] with 7 ft being the regulation size for pub pool league play

    Pockets

    British pool is played with 2" balls as opposed to the 2 1/4" American balls, with British balls generally being colour coded, such as Red/Yellow, Blue/Yellow as opposed to the spots and stripes of American Pool. This difference in ball size requires that the pockets on a British pool table be smaller (the ball size multiplied by 1.6 gives the opening pocket diameter). The pockets, especially the middle pockets, are much more rounded than those of an American pool table, similar to those of a snooker table. This affects the accuracy needed for middle-pocket shots and shots down the cushion into a corner pocket.

    Bed

    British pool tables are generally slate-bed, and certainly for tournament play this must be the case. However cheaper, more portable, home models are available with MDF bed.

    Snooker tables

    Snooker table, drawn to scale
    A billiard table designed for the game snooker is called a snooker table

    Dimensions

    A standard tournament snooker table measures 11 ft 8.5 in by 5 ft 10 in (3669 mm by 1778 mm), though commonly referred to as 12 ft by 6 ft. Smaller 9 ft 5 in by 5 ft 10 in (2895.6 mm by 1554.48 mm) tables (commonly referred to as 10 ft by 5 ft.) are also sometimes used. The height from the floor to the top of the cushion is between 2 ft 9.5 in and 2 ft 10.5 in (851 mm and 876 mm).

    Pockets

    A snooker table has six pockets, one at each corner and one at the center of each of the longest side cushions. The pockets are around 70 mm (3.5 in)[clarification needed], though high-class tournaments may use slightly smaller pockets to increase difficulty. The amount of "undercut" in the pocket determines how easily a ball is accepted. Compared to a billiards table, snooker table pockets are rounded, while pool tables have sharp corners. This affects how accurate shots need to be to get in a pocket and on rail shots from one end of the table to the other.

    Cushions

    The cushions (sometimes known as rails, though that term properly applies to the wood sections to which the cushions are attached) are usually made of vulcanized rubber.

    The bed

    The playing surface or "bed" of a good quality snooker table has a base of slate and is covered with green baize or worsted wool. The thickness of the cloth determines the speed, accuracy and responsiveness of the table to spin, thicker cloths being more hard-wearing but slower and less responsive. The nap of the cloth can affect the run of the balls, especially on slower shots. A snooker table traditionally has the nap running from baulk to the top end and is brushed and ironed in this direction.

    Markings

    The baulk area is marked by a line drawn at 29 in (740 mm) from the bottom cushion. A semicircle with a radius of 11.5 in (290 mm) centred on this line within baulk forms the "D" in which the cue ball must be placed when breaking or after the cue ball has been potted or shot off the table. The position of four of the colours are marked along the long string (lengthwise centre) of the table, perpendicular to the baulk line: the spot, or black spot, 12.75 in (324 mm) from the top cushion; the centre spot, or blue spot, located at the mid-point between the bottom and top cushions; The pyramid spot, or pink spot, located midway between the centre spot and the top cushion; and the brown spot, located at the mid-point of the baulk line. The exact placing of these markings will be different on smaller tables.

    Other billiard tables

    Other types of billiard tables are used for specific games, such as Russian pyramid, Asian four ball, and bumper pool. Also, British pool tables differ significantly from pool tables found in the USA. In addition, there are novelty billiard tables, typically for pocket billiards, that come in various shapes including zig-zag, circular, and hexagonal.














     



     


     

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