Counts of Yarn
Two Processes
We have now for the first time reduced the raw material to a continuous strand, comparatively free from impurities. Up to this point, no matter what kind of yarn is to be spun, the operations are practically identical, but from here on the processes vary according to the product desired. A hank of yarn is 840 yards (not to be confused with the worsted hank of 560 yards) and the number of hanks it takes to make a pound is the basis upon which yarn is classified. Thus a coarse yarn which weighs only twenty hanks to the pound, would be called 20s, while 80s would be a very fine yarn. Various fabrics require different grades of yarn, just as different finenesses of yarn must be spun from varying grades of cotton. The processes preparatory to spinning vary, not only with the counts to be spun, but with the use to which the yarn is to be put. Ordinary coarse and medium yarns for weaving usually follow one process, while fine counts for weaving, or knitting yarn, or coarse yarn made from long-staple cotton such as that used for tire-duck, go through a different preparation. The former are simply drawn and reduced, while the latter are in addition combed.
Drawing
First Process
Drawing
In the ordinary process, which is by far the most commonly used, the sliver from the card is put through successive similar operations, known as drawing, the object of which is to draw out the fibres and cause them to lie parallel to each other. Six card slivers are fed together between two pairs of rollers, the second of which is revolving faster than the first. The obvious result of this is the stretching of that portion of the slivers which is between the two sets of rollers. The operation is usually performed two or three times, in each case combining six strands into one. The sliver delivered by the third drawing machine will be of the same diameter as the original card sliver, but will contain more or less parallel fibres.
Roving Frame