Making a Good Selvage
To counteract this it is essential that great care should be taken to get a good clearance of the shed. The shed should be timed as early as possible, so as to give every particle of fibre on the warp a good chance to separate and clear itself. When space permits, the front reed should be set slightly over on one side of the reed space, so as to create a little longer pull on the filling as it draws from the shuttle on the open side, and correspondingly eases up the draw of the filling on the other side. The warp stock used, however, may be of such a character that the loose fibre on it makes even these precautions ineffective altogether to counteract the trouble, and it may then become advisable to put in a fine edge wire on the open side of the web to offset the creeping tendency of the selvage rubber thread when contraction takes place after the web comes through the press rolls.
The feature which is aimed at, and which is most desirable in the appearance of such goods, is a clean cut prominent rib at the rubber line, and the avoidance of a flat paper-like look and feel of the web generally. The prominence of the rib varies, of course, according to the size of the rubber thread used, and the binder warp employed in dividing the same, but even the very best of conditions may be spoiled if proper care is not taken to get all the prominence of rib possible. Use as fine a binder warp as is practicable, compensating for any loss of weight or excess of contraction by using a heavier gut, which again of itself helps to fill in the rubber cavity and thereby lends additional prominence to the rib. All the weight possible should be carried on the binder warp up to a point of safety, and care should be taken to get a very easy, uniform delivery of the warp from the beam so as to avoid any erratic jerky movement of the warp lever.
The warp beams which are used on this delicate type of work should be well balanced and true to center, and the flanges free from any irregularity which would in any way interfere with the easy and uniform operation of the warp lever.
The gut, which weaves in with the rubber thread, is used for the two-fold purpose of giving additional body to the fabric and of regulating in a measure the length of stretch in the goods. The more gut there is used, the less becomes the power of contraction of the rubber warp, and the shorter the stretch produced.
Aside from the fineness and body of the goods, the element of stretch largely governs the market value of the fabric, so that good judgment and great care must be exercised in the assembling of the different sizes of yarns used. Weft, binder and gut all play their part in the governing of the stretch, as also does the number of picks put in the goods. Any excess of weight on the binder warp also materially reduces the stretch. In fact, any one of these features, wrongly adjusted, may result in the difference between the profit and loss.
In making the selvage of these goods a hard steel wire is used, around which the filling passes at each pick. This wire, shown at W in Fig. 6A, is highly tempered piano wire, of the very best quality obtainable. Sharpened to a needle point at one end, with a loop turned at the other end, it is fastened at the back of the loom by a cord which has an adjustable slip knot, so as to be able easily and quickly to regulate the length of wire running in the web. It is then passed through a harness heddle eye on the rubber or gut shaft, and through a reed space next outside the selvage rubber thread. The constant wear of this wire on the reed dent makes it necessary to have this dent of hardened steel so as to withstand the constant wear of the wire, which is always being crowded against the dent by the nipping action of the filling as it draws against the wire in the process of weaving, and the repeated beat at the same place in the dent at the weaving line. In any event, after a short time the dents in the reed will be cut so that it becomes necessary to frequently replace them with new ones, and for this reason it should be so arranged that they can be easily and quickly removed from and replaced in the reeds.
The Lisle Web
The lisle web, being perfectly plain, is similar in general character to the loom web, except that it is made with high grade combed and gassed yarns for the filling in place of cheaper stock used on the loom webs, and is woven with four threads for the binder warp between each strand of rubber, instead of two as in the loom web. The harness draft of the one-half inch lisle web shown at Fig. 7, together with the weave, is shown at Fig. 7A. The construction is as follows: Binder, 36 ends 80/2; gut, 8 ends 40/2; rubber, 10 ends 32s; reed, 21 dent; picks, 78 per inch; stretch, 75 per cent.