5. Spinning
Drawing
The first processes in a spinning mill very closely approximate the last operations in the combing plant. The tops are usually gilled several times before weighing, and then are put through several drawing machines in which, as heretofore, several slivers are condensed into one. In the last of these machines there are no fallers, the entire process consisting of two sets of rollers revolving at different speed. Each operation results in a slightly finer sliver, and the number of machines through which the material is drawn is determined by the fineness of the yarn desired.
French
English
The last of the drawing processes is the so-called roving box, which, in most cases is a cone-drawing process. There is a difference here between French spinning and English spinning. According to the French system, which is employed in this country only for very soft fine yarns, no twist is given to the sliver until the actual spinning begins; and the spinning is then usually done on mules, which in this country are rarely used in the manufacture of worsted yarn. We shall discuss these machines when we come to woolens. According to the most common procedure in this country, the roving box not only draws, but imparts a certain amount of twist to the yarn. This is done by winding the yarn from horizontal spools on to vertical spindles. These spindles are set on long frames, similar to spinning frames, one frame containing about 200 spindles. The yarn is guided on the bobbin by an arm, known as the flyer, which draws the bobbin around after it.
Spinning
There is very little difference between this last drawing operation and the actual spinning which immediately succeeds it. In both cases the yarn is unwound from horizontal spools placed at the top of the frame through the inevitable two rollers going at different speeds, and guided on to the revolving spindle. Since the spindle revolves vertically the yarn is twisted. The amount of twist is regulated, as is also the amount of tension, and these two factors, together with the quality of the material, determine the quality of the yarn. Worsted yarn is graded according to the number of counts, which, as we have seen, is the number of hanks of 560 yards that make a pound avoirdupois.
Drawing
Flyer
Cap
Ring
Roughly speaking, there are three modern methods of spinning, namely, the flyer, cap, and ring frames. All of them are derived from Arkwright’s original water throstle, and, if we want to go further back, from the old-fashioned spinning wheel. The chief difference between the three types lies in the method of driving the spindle and guiding the yarn on to the bobbin. The flyer arm we have described briefly above. In the cap system, the bobbin is moved up and down in a fixed metal cap, something like the front end of a two-inch shell-casing, and this method of guiding the yarn has the advantage that, because of its lower vibration, the spindles may be driven faster. It also causes considerably more friction on the yarn. For worsted spinning it is probably the most commonly employed. Ring spinning, the most frequently used for cotton, and described briefly on page [28], is very similar (to the layman) except that the spindle revolves in a metal sleeve, and that the yarn is guided by a metal ring with a traveller, instead of by the end of the cap.
Reducing
Twisting
What follows now is merely an auxiliary process of spinning. The yarn has been completed, but it is rarely used for weaving, as it comes off the spindle. Several strands are usually twisted together, both to make it stronger and to give various effects of body and color. The number of strands in a yarn are designated as plys. Yarn consisting of two strands is called two-ply, three strands are three-ply, and so on. Yarns of two or more colors, or yarns of varying counts, are frequently twisted together. It is possible also to twist worsted and cotton yarns.
Cap spinning
Spindlage
Twisting is done in a manner similar to spinning. A worsted spinning mill usually has about a third as many twisting spindles as spinning spindles, but it is important to remember that when speaking of a mill’s capacity in terms of spindles, it is only the spinning spindles that are counted.
Winding or Skeining
After the twisting is completed the finished yarn is wound on small spools, known as cheesers, to be weighed. Next it is wound on large spools in such a way that the large spool holds the contents of from ten to twenty cheesers, each wound in an adjacent space at the same time. Some of the yarn is shipped to weaving mills on these large spools; and some of it is taken off them and skeined.
Waste
We are now ready to weave the cloth, but there are a considerable number of very interesting details which we have been forced to omit. All the processes we have discussed produce a certain amount of waste material. The combing waste, known as noils, is the largest by-product of the worsted industry, but there is also a considerable amount of yarn waste produced in the various drawing and spinning operations. Practically all of this material finds its way back, in one form or another, into the woolen industry. The subject of reclaiming waste is in itself so comprehensive that we can do no more than touch upon it here.