It will be seen that all the binder threads operate two up and two down, but change at each pick in rotation, making the repeat every four picks of the loom. In a weave of this character the changes of the harness are distributed uniformly at each pick, thus making it much easier to get uniform conditions on each selvage. It differs from the loom web in this respect, where the alternating light and heavy pick has to be contended with.
Like the loom webs, prominence of the rib over the rubber thread is the main feature aimed at in the general appearance of the fabrics, and therefore everything possible should be done which will emphasize this. The binder warp must be of fine yarns, and the warp must be weighted so as to cut the warp line down sharp and clear up to a point of safety, being careful at the same time not to go to excess so as to narrow in the goods or cause undue chafing of the rubber warp. The yarn most generally used for filling is 26-2 comber and gassed high grade stock, of about 15 turns per inch. It should be a well-rounded lofty yarn so as to obtain all the covering property possible. It should be spun with the utmost uniformity, as the slightest irregularity in the yarn will be noticeable in the goods.
The dyeing and bleaching of the yarn used for filling is also of the greatest importance. It is not an unusual occurrence to find otherwise perfect goods made unmarketable as first class by the use of a filling yarn which has not been properly processed. This faulty condition of the yarn may be caused in a variety of ways; such as an irregular boil, poor circulation of liquor in the kier, irregular drying, etc. Even when the color appears to be perfect, poor processing will often prevent the smooth running of the yarn from the shuttle, causing it to drag and thus create irregular and crooked selvages which result in the repeated breaking of the selvage rubber threads and ruin the goods.
The many difficulties of this character which were encountered when skein yarn was more generally used for filling led to the introduction and almost general use of warp yarns for filling purposes, inasmuch as the method of processing the warp yarns gives results which are not nearly so variable. Furthermore the long unbroken runs of thread obtainable by quilling avoid the many knots which are present when using skein yarn. Knots are unsightly and objectionable when appearing on the face of the goods.
Chafed and broken edge rubber threads, however, are not always the result of the conditions named, by any means, but may be caused by a variety of other things. Not infrequently the edge wire may be weaving too long in the web so as not to draw out freely. Sometimes it may be a bent wire that causes the trouble, or it may be the rubber rolling around the wire. Many times defects are caused by the edge wire having cut into the dent, so that it has a file-like effect as the rubber thread passes by in weaving. All these things require looking into, and when trouble comes the cause should be found and not guessed at.
French Web or Railroad Weave
Another plain web which has attained considerable popularity, and which is a kind of intermediate grade between the loom web and the lisle, is what is known as the French web or railroad weave, shown at Fig. 8. In almost all respects the general treatment of this web is the same as already described, and it differs only in the draft, which is shown at Fig. 8A. It allows for the use of a somewhat finer yarn than is generally employed in the loom web, and the draft changes at every two cords, which gives it a peculiar “rowey” appearance from which it derives the name of railroad weave.
There is one feature associated with all these plain webs which it might be well to speak of. The high tension at which it is necessary to work the rubber warp, together with the light weight required on the cotton warp and the crowding together of the picking, creates a tendency for the goods to rebound at the front reed, accompanied by a backward and forward sliding movement when passing over the rod at the breast beam. This movement is liable to polish the goods, which is an objectionable feature. To counteract this it is advisable to let the web pass over a small, felt-covered wood tube, which revolves and responds to the movement of the bounding web. In this way there is no friction to glaze or polish the web and interfere with the bloom of the yarn. The same polish will occur as the goods pass through the press rolls, unless they are felt covered.