Yarn

This article is about the fibre product. For the type of joke, see Shaggy dog story.

Yarn

Spools of thread

Yarn is a long continuous length of interlocked fibres, suitable for use in the production of textiles, sewing, crocheting, knitting, weaving, embroidery and ropemaking. Thread is a type of yarn intended for sewing by hand or machine. Modern manufactured sewing threads may be finished with wax or other lubricants to withstand the stresses involved in sewing. Embroidery threads are yarns specifically designed for hand or machine embroidery.

Materials

Yarn can be made from any number of natural or synthetic fibers.

Natural fibers

Cotton being spun

The most common plant fiber is cotton, which is typically spun into fine yarn for mechanical weaving or knitting into cloth. The most commonly used animal fiber is wool harvested from sheep. For hand knitting and hobby knitting, thick wool yarns are frequently used.

Other animal fibers used include alpaca, angora, mohair, llama, cashmere, and silk. More rarely, yarn may be spun from camel, yak, possum, qiviut, cat, dog, wolf, rabbit, or buffalo hair, and even turkey or ostrich feathers. Natural fibers such as these have the advantage of being slightly elastic and very breathable, while trapping a great deal of air, making for a fairly warm fabric.

Other natural fibers that can be used for yarn include linen and cotton. These tend to be much less elastic, and retain less warmth than the animal-hair yarns, though they can be stronger in some cases. The finished product will also look rather different from the woollen yarns. Other plant fibers which can be spun include bamboo, hemp, corn, and soy fiber.

Synthetic fibers

A number of synthetic materials are also commonly made into yarn, chiefly acrylic. All-acrylic yarns are available, as are wool-acrylic blends in various proportions. Some other synthetics are available as well; yarn designed for use in socks frequently contains a small percentage of nylon, and numerous specialty yarns exist.

Comparison of material properties

A full restored & operative primay level spinning machine taking freshly carded cotton tails from barrels & spinning them into yarn at the Quarry Bank Mill, UK.

In general, natural fibers tend to require more careful handling than synthetics because they can shrink, felt, stain, shed, fade, stretch, wrinkle, or be eaten by moths more readily, unless special treatments such as mercerization or superwashing are performed to strengthen, fix color, or otherwise enhance the fiber's own properties.

Protein yarns (hair, silk, feathers) may also be irritating to some people, causing contact dermatitis, hives, wheezing or other reactions. Plant fibers tend to be better tolerated by people with sensitivities to the protein yarns, and allergists may suggest using them or synthetics instead to prevent symptoms. Some people find that they can tolerate organically grown and processed versions of protein fibers, possibly because organic processing standards preclude the use of chemicals that may irritate the skin.

When natural fibers are burned, they tend to singe and have a smell of burnt hair; synthetic yarns tend to melt. Noting how an unidentified fiber strand burns and smells can assist in determining if it is natural or synthetic.

Synthetic yarns, because of their construction as long, extruded strands, do not pill the way natural yarns can.

Yarns combining synthetic and natural materials inherit the properties of each parent, according to the proportional composition. Synthetics are added to lower cost, increase durability, add unusual color or visual effects, provide machine washability and stain resistance, reduce heat retention or lighten garment weight.

Structure

Main article: Spinning (textiles)

A Spinning Jenny, spinning machine which was significant in the beginning of the Industrial Revolution

S- and Z-twist yarn

Spun yarn is made by twisting or otherwise bonding staple fibres together to make a cohesive thread, or "single." Twisting fibres into yarn in the process called spinning can be dated back to the Upper Paleolithic, and yarn spinning was one of the very first processes to be industrialized. Spun yarns may contain a single type of fibre, or be a blend of various types. Combining synthetic fibres (which can have high strength, lustre, and fire retardant qualities) with natural fibres (which have good water absorbency and skin comforting qualities) is very common. The most widely used blends are cotton-polyester and wool-acrylic fibre blends. Blends of different natural fibres are common too, especially with more expensive fibres such as alpaca, angora and cashmere. Bamboo yarn is a less expensive type that is a recent innovation.

Yarns are selected for different textiles based on the characteristics of the yarn fibres, such as warmth (wool), light weight (cotton or bamboo), durability (nylon is added to sock yarn, for example), or softness (cashmere, alpaca). Acrylic yarn is the least expensive.

Yarns are made up of a number of singles, which are known as plies when grouped together. These singles of yarn are twisted together (plied) in the opposite direction to make a thicker yarn. Depending on the direction of this final twist, the yarn will be known as s-twist or z-twist. For a single, the direction of the final twist is the same as its original twist.

Filament yarn consists of filament fibres (very long continuous fibres) either twisted together or only grouped together. Thicker monofilaments are typically used for industrial purposes rather than fabric production or decoration. Silk is a natural filament, and synthetic filament yarns are used to produce silk-like effects.

Texturized yarns are made by a process of air texturizing (sometimes referred to as taslanizing), which combines multiple filament yarns into a yarn with some of the characteristics of spun yarns.

Color

Yarn comes in many colors

Yarn may be used undyed, or may be colored with natural or artificial dyes. The colours can be very pretty Most yarns have a single uniform hue, but there is also a wide selection of variegated yarns:

• heathered or tweed: yarn with flecks of different colored fiber
• ombre: variegated yarn with light and dark shades of a single hue
• multi-colored: variegated yarn with two or more distinct hues (a "parrot colorway" might have green, yellow and red)
• self-striping: yarn dyed with lengths of color that will automatically create stripes in a knitted or crocheted object
• marled: yarn made from strands of different-colored yarn twisted together, sometimes in closely related hues

Measurement

A comparison of yarn weights (thicknesses): the top skein is aran weight, suitable for knitting a thick sweater or hat. The manufacturer's recommended knitting gauge appears on the label: 8 to 10 stitches per inch using size 4.5 to 5.1 mm needles. The bottom skein is sock weight, specifically for knitting socks. Recommended gauge: 5 to 7 stitches per inch, using size 3.6 to 4.2 mm needles. These yarns are manufactured in Japan and have variegated colours in a random-dyed pattern.

Spool of all purpose sewing thread, closeup shows texture of 2-ply Z-twist mercerized cotton with polyester core.

Yarn drying after being dyed in the early American tradition, at Conner Prairie living history museum.

Yarn quantities are usually measured by weight in ounces or grams. In the United States, Canada and Europe, balls of yarn for handcrafts are sold by weight. Common sizes include 25g, 50g, and 100g skeins. Some companies also primarily measure in ounces with common sizes being three-ounce, four-ounce, six-ounce, and eight-ounce skeins. These measurements are taken at a standard temperature and humidity, because yarn can absorb moisture from the air. The actual length of the yarn contained in a ball or skein can vary due to the inherent heaviness of the fibre and the thickness of the strand; for instance, a 50 g skein of lace weight mohair may contain several hundred metres, while a 50g skein of bulky wool may contain only 60 metres.

There are several thicknesses of yarn, also referred to as weight. This is not to be confused with the measurement and/or weight listed above. The Craft Yarn Council of America is making an effort to promote a standardized industry system for measuring this, numbering the weights from 1 (finest) to 6 (heaviest). Some of the names for the various weights of yarn from finest to thickest are called lace, fingering, sport, double-knit (or DK), worsted, aran (or heavy worsted), bulky, and super-bulky. This naming convention is more descriptive than precise; fibre artists disagree about where on the continuum each lies, and the precise relationships between the sizes.

A more precise measurement of yarn weight, often used by weavers, is wraps per inch (wpi). The yarn is wrapped snugly around a ruler and the number of wraps that fit in an inch are counted.

Labels on yarn for handicrafts often include information on gauge, known in the UK as tension, which is a measurement of how many stitches and rows are produced per inch or per cm on a specified size of knitting needle or crochet hook. The proposed standardization uses a four-by-four inch/ten-by-ten cm knitted or crocheted square, with the resultant number of stitches across and rows high made by the suggested tools on the label to determine the gauge.

In Europe textile engineers often use the unit tex, which is the weight in grams of a kilometre of yarn, or decitex, which is a finer measurement corresponding to the weight in grams of 10 km of yarn. Many other units have been used over time by different industries.

Some yarn retail stores try to help the customer choose yarn by attaching a sample knitted square to the shelf holding each display of a particular weight of yarn, sometimes provided by the manufacturer. These samples are knit in the industry standard four-by-four inch / ten-by-ten centimetre gauge. Samples help the buyer by showing them the texture and thickness of the finished knit fabric.

See also

self-striping yarn

• Crochet thread
• Dye lot
• Electrically conducting yarn
• Embroidery thread
• ISO 2
• List of novelty yarns
• List of yarns for crochet and knitting
• Textile manufacturing
• Yarn bombing