Skip and Pointed Twills
Skip twills are a type of broken twill effects formed by a skip drawing-in draft and a regular twill weave as a chain draft. The weaves that form a wave effects across the cloth known as pointed twills. These effects are also frequently spoken of as herring banes, or herring-bones stripes, because the radiating twill lines suggest the radiating bones of a fish’s backbone.
What are Skip Twills?
These are a type of broken twill effects formed by a skip drawing-in draft and a regular twill weave as a chain draft. The drawing-in draft is made so that the ends are drawn in straight for a certain number of harnesses; a number of harnesses are then missed, and afterward, the ends are again drawn in straight.
The draft is so constructed that when the harnesses are skipped, the end in the harness just before the skip will rise and fall exactly opposite to the next end; by this means a broken effect is formed in the cloth. In Fig. 45 (a) is shown a skip twill that is made with the 6—end regular twill 3/3, Fig. 45 (c), as a chain draft and the skip drawing-in draft shown in Fig. 45 (6). In this draft the first 3 ends are drawn straight; then 2 harnesses are skipped; 3 more ends are then drawn straight, and so on until a repeat is found.
In this weave, the fourth end rises and falls exactly opposite to the third end. This is accomplished by means of drawing the fourth end through the sixth harness instead of the fourth, as would be done with a straight draft. The seventh and rises and falls exactly opposite to the sixth, the tenth end opposes the ninth in the same manner, and so on until the eighteenth end is reached, which rises and falls exactly opposite to the first end. One end rising and falling in opposition to another in this rnan¥ ner is termed matting. Skip twills are best constructed from equally flushed twills.
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What are Pointed Twills?
Another class of twill weaves obtained by means of the harness draft includes those weaves obtained by point drafts, which form wave effects across the cloth known as pointed twills. These effects are also frequently spoken of as herring banes, or herring-bones stripes because the radiating twill lines suggest the radiating bones of a fish’s backbone. Suppose that it is desired to make a pointed, or wave, effect with. the 45° twill shown in Fig. 46 (a) as the chain draft; Fig. 46 (b) shows the harness draft that will be used, while Fig. 46 (c) shows the effect obtained in the cloth. One important point in connection with point drafts is that they always end on the second harness and not on the first, that is, assuming that the draft begins on the first harness For instance, in Fig. 46 (b), the; ends are drawn straight for the first 8 harnesses, when they are reversed, commencing with the seventh harness; when the harness draft reaches the second harness after being reversed, one repeat of the draft is obtained.
If the last end of the draft were drawn through the First harness, the first and last ends of each repeat would work exactly alike, which would give in the cloth 2 ends side by side working alike. This would cause a serious defect in the fabric. If the weave is shown in Fig. 46 (c) is repeated two or three times in both ends and picks, a better idea of the waves formed by these weaves will be obtained. Many good effects can be obtained by this method by changing the harness draft and using the same chain draft. Thus, instead of using a regular point draft like that shown in Fig. 46 (6), a draft like that shown in Fig. 47 (a) may be used; the effect, or weave, in this case, will be similar to that shown in Fig. 47 (b).
The point twills thus far described will make waves across, or widthwise of, the cloth. The same effects, however, may be made to extend lengthwise of the cloth by simply reversing the chain draft in the same manner that the harness draft was reversed when making waves across the cloth. Suppose that it is desired to make a chain draft that will give a wave running lengthwise of the cloth from the twill shown in Fig. 48 (a).
It is simply necessary to make a chain draft that will have the first 12 picks similar to Fig.48 (a) and the remaining picks made by reversing these first 12 picks; that is, the thirteenth pick will be like the eleventh; the fourteenth, like the tenth; the fifteenth, like the ninth; the sixteenth, like the eighth; the seventeenth, like the seventh; the eighteenth, like the sixth; the nineteenth, like the fifth; the twentieth, like the fourth; the twenty—first, like the third; and the twenty-second, like the second. Here the chain draft will stop, in order to avoid having the first and last picks alike, on the same principle that the harness drafts of weaves making waves across the cloth stop on the second harness. Fig. 48 (b) shows the’ chain draft to give the wave lengthwise of the cloth; the harness draft will be a 12-harness straight draft.