Wool classing

Wool classing is an occupation for which people are trained to produce uniform, predictable, low risk lines of wool. This is carried out by examining the characteristics of the wool in its raw state. The characteristics which a wool classer would examine are:

Breed of the sheep: Shedding breeds will increase the risk of medulated and/or pigmented fibres. Any sheep likely to have dark fibres should be shorn last to avoid contamination. The age of the sheep will have a bearing on the fibre diameter and value of wool, too.

Chemical usage: Ensure that all rules have been followed.

Brands, seedy jowls and shanks: Must be removed from fleeces and broken.

Stain: Must be removed from bellies and fleeces and identified in a separate line.

Wool crimp: The number of bends per unit length along the wool fibre approximately indicates spinning capacity of the wool. Fibres with a fine crimp have many bends and usually have a small diameter. Such fibre can be spun into fine yarns, with great lengths of yarn for a given weight of wool, and greater market value. Fine fibres may be utilised in the production of fine garments such as men's suits whereas the coarser fibres may be used for the production of carpet and other sturdy products. Crimp is measured in crimps per inch or crimps per centimetre. Average diameter or mean fibre diameter is measured in micrometres (microns). For generations, English wool-handlers categorized wool along the above lines estimating spinning capacity by eye and touch. This spread worldwide as the Bradford system.

Wool Strength (also known as tensile strength) determines wool's ability to withstand processing. Weaker wools produce more waste in carding and spinning. Weaker wools may be used for production of felt, or combined with other fibres, etc.

Wool colour: Indicates whether wool is able to be dyed in light shades. Colour may be graded depending upon the natural colour, impurities and various stains present. Severely stained wool decreases prices dramatically. However, it is difficult to assess colour accurately without proper measurement, since some stains will wash out in the processing, whereas others are quite persistent.

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