Yarn, so far as the fully-fashioned stocking industry is concerned, refers to the prepared threads of fibres as they are received in the factory ready for knitting. There are four main types of yarn used for the production of stockings. They are those manufactured from wool, cotton and silk, and those that are man-made. This last type is composed of two distinct varieties. Some man-made fibres are produced from the cellulose to be found in wood or the short, otherwise useless, fibres surrounding the seed of the cotton plant, known as linters. These are not to be confused with the ordinary cotton fibres which are made directly into yarn for weaving and knitting. Cellulose man-made fibres are produced by treating wood pulp, linters pulp or other vegetable material with strong caustics and using the gummy substance that is developed as a thread. To turn the sticky liquid into dry yarn, it is first squirted into a chemical bath which hardens it and it is then ready for use in the construction of the yarn. The man-made fibres in this group are called rayons.

The other principal group of man-made fibres is represented by nylon. As can readily be seen, all that is achieved in the production of rayon is the alteration of cellulose from being a sticky mass into being a thread-like substance: in the production of nylon and similar “synthetics” no cellulose is involved and a completely new substance is made from chemicals which, by themselves, have no relation at all to fibres. The principal raw materials for the manufacture of nylon are coal and air and it is the action of chemicals extracted from the latter on those extracted from the former that produces nylon. The filaments of rayon and nylon yarns can be made to any length, but, with one exception, are not used singly in the production of garments except when 15 denier nylon is used for this is of single filament. For stocking yarn a number of filaments are twisted together to give greater strength and flexibility. This is generally true of all types of filament yarn used in stocking manufacture and this particular work of twisting is done by firms known as “throwsters”.
Silk is the natural product of the silkworm and is made simply for the construction of the protective coating to its eggs. A cocoon of silk contains anything between one thousand and three thousand yards of filament. It has one disadvantage as a raw material—that according to the weather and the state of health of the silkworm so the thickness of the filament that it produces varies. In man-made yarns there is no such difficulty as it is possible to control within very fine limits the diameter of the yarn’s filaments that are being formed. To overcome the variations in natural silk, hosiery factories use a special method of knitting called “ringfree”.