Care for Selvage
The threads must be properly divided in the front reed so as to make a good clearance for the filling, which otherwise would “nib” up and make an unsightly selvage. Then again, a careful adjustment of the weight carried on the selvage warp must be made so as to accommodate it to the requisite tension of the filling as it is delivered from the shuttle, otherwise the edge rubber threads will be liable to chafe and cut off when strained out of proper alignment with the front reed. It will be observed in the draft that two rubber threads are used in each selvage, which is necessary in order to control the additional yarn used in the construction of the selvage.
Chapter V.
Three Leaf Twill or Satin Face Woven in Conjunction with Plain Back—Position of Back Rolls in Relation to Harness Shed—Use of Four Leaf Twill—Filling Fancy Effects and Stitch Figures—Interchanging Figure and Face
Turning our attention from plain webs to combination weaves, we will take up what is popularly known as the three-leaf twill, or satin face, woven in conjunction with a plain back. This is a type of web not only used for suspenders, but employed extensively for corset garter attachments also. A web of this character when properly constructed has a smooth velvet-like face. The threads are uniformly distributed across the width without showing any of the “rowy” effect from the binder warps, which are completely hidden by the heavy pile produced by the float of the face threads. When the contraction of the web takes place, these floating face threads mass together in a velvet-like pile, not only producing a smooth handling web but materially increasing the thickness. Such webs are generally constructed with a six-thread face and a four-thread back, and have what is termed a round edge, similar to the selvage used on a plain web. This arrangement shows up the twill face by contrast and gives the fabric a much finer appearance.
Harness and Chain Draft
Fig. 1 shows the harness and chain draft of such a web, together with the construction of a properly balanced web for standard goods of 1⅛ inches wide. It will be noticed that the face, consisting of 150 threads, is split up into two warps of 75 threads each. This arrangement is necessary in order properly to weigh them so as to get a good clearance in the shed. The warp has to be divided likewise in the harnesses and put on six harness frames, although the weave could be produced on three. It would not be practicable to crowd 50 threads on one harness frame in the narrow space available, as the harness eyes would shoulder and crowd too much when changing.
In drawing-in this web, one face warp should be arranged so that the threads are drawn on the first, third and fifth harnesses, and the other face warp should be on the second, fourth and sixth. Such an arrangement in the distribution of the warps makes it much easier on the mechanism, and minimizes the risk of breakages. It is also important to make proper divisions of the warps at the back rolls, inasmuch as some of the warps have to be weighted heavily while others are only lightly weighted, and also on account of the different take-up of the varied weaves.
The back rolls should be set in a graded position so as to prevent undue friction of one warp against another. The binder warp should be worked under the front roll on account of the extremely light weight this must carry. Fig. 2 shows the proper position of the back rolls in relation to the harness shed.