Wool Standards
The fibre of wool, the fleece of the domesticated sheep, is made up of three or four layers. In medium and coarse wools, the innermost layer is the medulla. The next layer is the cortex; then the cuticle, made of overlapping scales; and finally, a thin outer membrane called the epicuticle.
Both the length and the diameter of wool fibre determine its end use. The term staple length refers to the stretched length of a fibre. Staple length is important in judging what kinds of machine-processing are best suited for a given type of wool. The diameter of a fibre indicates its fineness and softness and feel against the skin. Diameter is now measured in microns, or 1/1000 millimeter. Before machine measurement was widespread, a common form of measurement was the spinning count. The higher the number, the finer, and usually shorter and straighter the fibre.
IMAGE TBD BELOW: MICROSCOPY IMAGE SHOWING SCALES
The growth of consumer demand for ever softer and finer woolen textiles (itself a product of innovations such as central heating), was impacted by, and spurred innovation in, the science of fibre measurement. The processes of grading, evaluating, and buying wool were originally the province of wool classers and wool buyers who relied on the knowledge in their fingertips to determine the fineness and quality of wool fleece. Skills needed to judge which wools would best make a particular end product were acquired in the field and in classrooms, and refined over years of handling fleeces in the raw. These skills were largely dispensed with once the machines that measured, scientifically, the fibre diameter, came into common use in the 1970s.
Merino spinning counts in the early 20thcentury were 80s, 72s, 70s, 66s, 64s, 60s super, and 60s ordinary. In crossbred wools, the counts were 58s, 56s, 50s, 46s, 44s, 40s, 36s, and 32s. Translated into English, this means that one pound of 80s quality fiber will spin a thread 80 times 560 yards long – one pound of clean and carded 80s wool, ready for spinning, makes a yarn something over 25 miles long. In contrast, one pound of 40s quality will spin a thread 40 times 560 yards long, almost 13 miles.
In 1968, the United States Standards for Grades of Wool defined equivalencies between the spin counts and micron measurements. For example, wool with an average fiber diameter of 17.69 microns or less qualified as “Finer than Grade 80s.” At the other end of the spectrum, “Coarser than grade 36s” wool has an average diameter of more than 40.21 microns.
A sheep’s fleece could be graded into many qualities of wool fibers. Fiber diameter (fineness) was an important factor in what products the wool could be used to manufacture, and in its price. Standards boxes ensured that wool grades were clear to both sellers and buyers. The 1926 standards distinguished 12 grades of wool by fiber diameter. This group of three samples shows the finer grades. By 1968 the U.S. classification had 16 grades, from Finer than grade 80s, down to Coarser than grade 36. Notice that the one marked “36” is also labeled “Braid”. This suggests that this type of wool was best suited to manufacturing durable upholstery and garment trimmings, such as braids or cords.
In this photograph, some of Western Australia's wool clip for 1917 is being appraised (classified and valued for staple length and fineness) for acquisition by the British government for its wartime needs. In November 1916, Britain and Australia agreed that instead of the peacetime system of private auctions, all Australian wool would be sold to Britain for the duration of the war that we know today as World War I.
The wool trade was of keen importance to the Australian and New Zealand economies, one reason why returning soldiers, in both the first and second world wars, were given training as wool classers. Returning soldiers were promised jobs in the wool industry. Some were offered the hope of a fresh start raising sheep on a small land allotment - a hope that often proved false, as available land sometimes proved inadequate for sustaining sheep.
The American Woolen Co. was one of the U.S.'s largest manufacturers of woolen fabrics. Manpower shortages spurred by America's entry into World War I in 1917 led to occupations that had been viewed strictly as a man's job, such as wool classing, being opened to women.