Spinning

spinning, the drawing out, twisting, and winding of fibers into a continuous thread or yarn. From antiquity until the Industrial Revolution, spinning was a household industry. The roughly carded fiber was at first held in one hand and drawn out and twisted by the other hand. The earliest tools were the distaff, a stick on which the fiber was wrapped, and the spindle, a shorter, tapering stick notched at one end and weighted by the wharve or whorl (a disk of stone or clay). The spindle was twirled to twist the thread, which was then wound on it. With these simple tools were spun extremely fine yarns. In India the delicate threads for the famed Dacca muslin were produced by revolving needle-thin pieces of bamboo in a coconut shell. The primitive Gurkha wheel was used to spin coarse yarns. In Europe from the 14th to the 16th cent. the distaff and spindle were gradually superseded by the spinning wheel. It consisted of a spindle set in a frame and revolved by a driving belt passing over a wheel. The great, or wool, wheel, revolving the spindle directly, then by a pulley, twisted the thread; it was then stopped and revolved in the opposite direction to back off the spun yarn, which was then wound on the spindle. The flax, or Saxony, wheel—a more elaborate mechanism operated by a treadle—drew, twisted, and wound the yarn with a continuous motion suited to flax, wool, or cotton. In England improvements of the loom in the 18th cent., increasing the demand for yarn, stimulated inventions that revolutionized spinning. John Wyatt suggested the use of rollers to attenuate the yarn, a process patented in 1738 by his partner, Lewis Paul. James Hargreaves invented c.1765 the spinning jenny, a frame capable of spinning from 8 to 11 threads at once. The softly twisted yarns were not suitable for use as warp threads, but in 1769, Richard Arkwright brought out his frame, which by means of successive pairs of rollers, each revolving faster than the preceding pair, attenuated the yarn and twisted and wound it on bobbins in a continuous action. Operated at first by horse or mule power, later by water power, and still later by steam, spinning rapidly became a factory enterprise. In 1779, Samuel Crompton, combining the best features of the jenny and of Arkwright's frame, invented the mule spinning frame, forerunner of the modern self-acting mule. Because of its intermittent action, the mule is used for fine or delicate yarns. For the mass production of coarser yarns, the ring frame, an elaboration of Arkwright's machine, invented by John Thorp c.1828, draws, twists, and winds the thread in one rapid, continuous operation.

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spinning

In metalwork, a technique for making hollow metal utensils and artifacts. Developed in the 19th century, the method can be used for most metals. A metal disk is set on a lathe behind an appropriately shaped metal or wooden chuck; while the lathe is rotating, the metal is pressed onto the chuck with a tool. A typical modern spun object is the aluminum saucepan. As in most metalworking techniques, the metal is periodically softened by annealing, or heating, when it has become hardened by being worked (see hardening).

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Spinning (metals)

A production technique for shaping and finishing metal. In the spinning of metal, a sheet is rotated and worked by a round-ended tool. The sheet is formed over a mandrel. Spinning may serve to smooth wrinkles in drawn parts, provide a fine finish, or complete a forming operation as in curling an edge of a deep-drawn part. Spun products range from precision reflectors and nose cones to kitchen utensils.

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Spinning (textiles)

The fabrication of yarn (thread) from either discontinuous natural fibers or bulk synthetic polymeric material. In a textile context the term spinning is applied to two different processes leading to the yarns used to make threads, cords, ropes, or woven or knitted textile products.

Natural fibers, such as wool, cotton, or linen, are generally found as short, entangled filaments. Their conversion into yarn is referred to as spinning. After a carding operation on the raw material to disentangle the short filaments, the filaments are drawn (drafted) to promote alignment in an overlapping pattern and then twisted to form, by mechanical interlocking of the discontinuous filaments, a resistant continuous yarn.

The term spinning is also used for the production of monofilaments from synthetic polymers—for example, polyamides or nylons, polyesters, and acrylics—or modified natural polymers, such as cellulose-rayon. Generally the monofilaments are stretched (drawn) to increase their strength by promoting molecular orientation and are wound as yarn which can be used directly for threads, cords, or ropes. Such yarn, however, is often cut into relatively short lengths (staple) and reformed by a process similar to that used for natural fibers into a yarn more suitable, in terms of appearance and feel, for making certain textile products. See Textile