The fancy twill is formed by placing small spots between the main lines of twill. The first end of the weave should be a continuation of the last end and the first pick should be a continuation of the last pick, so that the weave will continue perfectly when repeated in either direction.
About Fancy Twills
In addition to the regular 45° twills, there are many other twill weaves that may be considered as subdivisions of regular twills; these are very useful in many classes of fabrics. The first of these weaves that will be considered are those known as fancy twills. These weaves generally consist of a regular twill weave between the twill lines of which are placed sometimes other twills running in the opposite direction, sometimes small spots, and sometimes other small weaves. The first step in making such weaves is to construct a bold line of twill running across the design, as shown in Fig. 33.
In order to change this regular twill into a fancy twill, it is necessary to insert some other weave on the blank squares. Fig. 34 shows this twill changed to a fancy twill; the method employed is that of running short lines of twill in a direction opposite to that of the main line of twill. Figs. 35 and 36 show two other fancy twills. In Fig. 35, the fancy twill is formed by placing small spots between the main lines of twill; while in Fig. 36, the fancy twill is formed by placing a small weave, as shown, between the main lines of twill.
In making these weaves it should be noted that the entire weave runs up in a twill line and that it is essential to have the first and last ends and also the first and last picks match; that is, the first end of the weave should be a continuation of the last end and the first pick should be a continuation of the last pick, so that the weave will continue perfectly when repeated in either direction.
In order to accomplish this, it is necessary to have the spot or weave that is inserted occupy a number of picks that can be divided into the number of picks on which the entire weave is complete; otherwise, it, will be necessary to continue the twill and spot weaves until a point is reached where they repeat together, which will occur on a number of picks equal to the least common multiple of the number of picks required by the twill and by the spot weave. In Fig. 34, the small twill weave may be said to occupy 4 picks, which is exactly divisible into 16, the number of picks that one repeat of the completed weave occupies.
In Figs. 35 and 36, each inserted weave may be said to occupy 4 picks; this number is exactly divisible into 16, the number of picks that the complete weaves occupy.When the weave that is inserted between the twill lines repeats on a different number of picks, the twill and inserted weave are both repeated in the picks until they repeat together, which occurs on a number of picks equal to the least common multiple of the number of picks on which the twill and spot weave are complete.
For instance, suppose that it is desired to make a fancy twill weave by inserting Fig. 37 between the twill lines of a 6 twill. Fig. 37 is complete on 6 picks, while the twill requires 8 picks; therefore, the completed fancy twill will require 24 picks, since 24 is the least common multiple of 6 and 8 and both will not commence repeating together until the twenty-fifth pick. Fig. 38 shows the fancy twill thus obtained.
Entwining twills are constructed from regular twills by running sections of twill lines both to the right and to the left so that each section meets other sections at right angles. As their name indicates, the effects produced by these twills have an entwined or interlaced appearance; the more perfect ones are obtained when the separate sections are composed of equally flushed twills, although in some cases unequally flushed twills give good results.
Fig. 39 shows an entwining twill constructed by running two twill lines of the cassimere to the right and two to the left, the weave repeating on 8 ends and 8 picks. Although two repeats in the ends and two in the picks are shown here, when constructing these twills, the number of ends and picks that one repeat of the weave will occupy must be ascertained in the start. This may be found by multiplying the number of ends and picks require or one repeat weave used by the number of twill lines in each section; thus, since in Fig. 39 two twill lines of the cassimere, or %, twill are used, the completed entwining twill occupies 8 ends and 8 picks (2 >< 4 = 8).
If it is desired to construct an entwining twill with the cassimere twill and have three twill lines in each section, 12 ends and 12 picks (3 X 4 = 12) will be required to show one repeat; if four twill lines in a section are wanted, 16 ends and 16 picks will be required, and so on. If the 6-end regular twill di is used as a base instead of the cassimere and three twill lines are desired in each section, 18 ends and 18 picks (3 >< 6 = 18) will be required for one repeat of the completed entwining twill.
In constructing an entwining twill, therefore, it is first necessary to decide on the twill weave to be used as a base and also on the number of twill lines to be used in each section, from which the number of ends and picks required for one repeat can be found.To illustrate the method of constructing these weaves; suppose that it is desired to make an entwining twill with the cassimere twill -27, having five twill lines in each section, which will give an entwining twill complete on 20 ends and 20 picks (5 >< 4 = 20).
The first step is to run up the first twill line of one section, as shown in Fig, 40 (a), continuing it for a number of ends equal to one—l1alf the total number of ends to be occupied by the repeat. Next insert the first twill line of the section of twill lines that run in the opposite direction, starting it on the next end to and just above the last riser of the first twill line and running it down in the opposite direction, as shown in Fig. 40 (b).
Next return to the first section, that is, the one running to the right, and complete it by running the four other twill lines parallel to the first twill line that has already been obtained. Each twill line must be continued, as shown in Fig. 40 (e), until it occupies the same number of ends as the first twill line; namely, a number of ends equal to One—half of the number occupied by the completed weave, or in this case 10 ends.
By completing the section of twill when the warp floats over more than 2 picks in a twill used as a base of the entwining twill, it is usually advisable to add one or more extra risers to the ends of each warp twill line in order to make the twill lines meet each other better and also to shorten the warp floats on the back of the cloth at the junction of the right and left twill lines.
For instance, Fig. 41 (a) shows an entwining twill constructed with three lines of the 3/3 regular twill in each section, and while this weave is perfectly constructed, if one extra riser is added to each end of every twill line as shown in Fig 41(b), the weave will be enhanced in value.
It is very often necessary to alter the ends of each twill line, either by adding or by taking out risers in order to make each twill line meet others in the best possible manner; especially is this true in the case of entwining twills based on unequally flushed weaves. As the repeat of the weave is already determined, the addition of extra risers will not alter the number of ends and picks in the repeat nor the number of harnesses necessary to weave the design.