Project Gutenberg's Theory Of Silk Weaving, by Arnold Wolfensberger This eBook is for the use of anyone anywhere at no cost and with almost no restrictions whatsoever. You may copy it, give it away or re-use it under the terms of the Project Gutenberg License included with this eBook or online at www.gutenberg.org Title: Theory Of Silk Weaving Author: Arnold Wolfensberger Release Date: January 5, 2005 [EBook #14600] Language: English Character set encoding: ISO-8859-1 *** START OF THIS PROJECT GUTENBERG EBOOK THEORY OF SILK WEAVING *** Produced by Stan Goodman, Keith Edkins and the PG Online Distributed Proofreading Team THEORY OF SILK WEAVING THEORY OF SILK WEAVING A Treatise on the Construction and Application of Weaves, and the Decomposition and Calculation of Broad and Narrow, Plain, Novelty and Jacquard Silk Fabrics Containing 95 Plates By ARNOLD WOLFENSBERGER Graduate of the Textile Institute of Zurich, Switzerland Second Revised and Enlarged Edition NEW YORK Issued by THE AMERICAN SILK JOURNAL CLIFFORD & LAWTON Publishers 1921 COPYRIGHT. 1921. by CLIFFORD & LAWTON [pg 1] [pg 3] [pg 4] All rights reserved GROLIER CRAFT PRESS, Printers. 229 West Twenty-eighth Street, New York City PREFACE The silk industry of America has of late years rapidly advanced to the front rank among the great textile industries of the world. It may indeed be proud of this position, to which that enterprising spirit and untiring energy peculiar to our nation, combined with our great technical and natural resources, has brought it. That we are, on the other hand, not yet at the height of perfection we are also compelled to acknowledge, but if we consider the short space of time that the American industry has required for its development, as compared to the decades, almost centuries, to which some of the great European silk centers can look back, the fact is neither surprising nor discouraging. While it must not be our aim to imitate or copy their ways, inasmuch as out conditions and circumstances are quite different from theirs, we may still profitably study their methods in order to overcome our deficiencies. The greatest advantage which our competitors derive from such a long existence consists in having at their disposal a force of skilful, trained help. The manufacturers, appreciating the importance of this factor, make great efforts and pecuniary sacrifices to elevate and maintain the high standard of their industry. For instance, they support textile schools and lecture courses, where young men can acquire a thorough technical education and equip themselves for a career of usefulness, thereby serving their own interests and at the same time furthering those of their chosen profession. This beneficial influence cannot fail to exert itself from the standard of the higher employer down to that of the weaver, who would naturally take more pains and interest in his work than if he were a mere mechanical appendage to his loom in order to keep it in motion. Very little has been done in his country for technical education as far as the silk industry is concerned, and it was on this special branch, that prompted the author to offer in the present little work a treatise on the theory of shaft weaving for broad silks and ribbons. It is divided into three principal parts: 1st. Drawing-in the warp in the harness. 2nd. The weaves and their application. 3rd. Decomposition or analysis of the cloth. To the foregoing there have been added in the revised and enlarged edition several additional parts covering the following: JACQUARD WEAVES, BOX LOOM WEAVES, including CREPES, and COST CALCULATIONS for plain and fancy weaves. The subject while condensed, is made as clear and comprehensible as possible, and to many desirous of increasing their knowledge in this direction, this should prove a valuable help. The author, through the medium of this work, hopes to win the approval and encouragement of the manufacturers, and will feel amply repaid should his efforts tend to develop a deeper interest in the "Queen of Textiles." THEORY OF SILK WEAVING DRAWING-IN With this term we designate the operation preceding the weaving, by which all the warp-threads are drawn through the heddles of the harness. The order in which this is done varies according to the weave and the nature of the fabric to be produced; so we distinguish: Straight draws, Skip draws, Point draws, Section draws. [pg 5] [pg 6] [pg 7] STRAIGHT DRAWS Fig. 1 Fig. 2 These form the simplest and most common method of drawing-in. We begin with the first heddle on the left side of the shaft nearest to the warp-beam, then take the first heddle of second shaft and so on until all the shafts the set contains are used in rotation. This completes one "draw," and this operation is repeated until all the warp-threads are taken up. The method of making the shaft nearest to the warp-beam the first, is almost universal with the silk business and is technically called drawing-in from back to front. The opposite, or drawing in from front to rear, is used occasionally, however, and in this case makes the first heddle on the left hand side of the front shaft No. 1. The making out of the Drawing-in Draft, which must indicate the arrangement or the rotation in which the warp- threads are drawn in, can be done in various ways, of which we will mention the two most popular methods. The first is by using common designing paper, and indicating the rotation by dots. The horizonal rows of squares represent the shafts, the vertical rows the warp-threads. Fig. 1 shows four repeats of a straight draw on six harness marked out according to this idea. A second method is to use paper ruled horizontally, the lines representing the shafts; and to draw vertical lines for the warp-threads. The latter are made to stop on the lines bearing the number of the shafts into which the respective threads are to be drawn. Fig. 2 is such a draft, illustrating six repeats of a draw on four harness from "Front to Rear." SKIP DRAWS Fig. 3 Fig. 4 The draws coming under this heading are used very extensively in silk weaving, especially for fabrics requiring a heavy warp and a large number of shafts. Enter first the odd and then the even shafts. An 8 harness draw of this kind, of which three repeats are shown in Fig. 3, runs as follows: 1, 3, 5, 7, 2, 4, 6, 8. Fig. 4 is a 12 harness draw of the same class. [pg 8] [pg 9] POINT DRAWS Fig. 5 Fig. 6 Fig. 7 Fig. 8 Fig. 9 Point draws are a combination of a regular straight draw from back to front and one from front to back, the first and the last shafts only being used once, while the rest receive two ends each in one repeat of the draw. Fig. 5 illustrates a regular point draw in 2 repeats on 10 shafts. It will be seen that 14 ends make a repeat; in fact, the number of warp- threads required for one draw will always be double the number of harness less 2, hence a 12 harness regular point draw will require 22 warp-threads for a repeat. The drawing-in draft illustrated in Fig. 6 is a slight variation of the regular point draw; it consists, as will be seen, of a draw from back to front, and also a full one from front to back, there by causing a double point. Another change from the regular point draw is illustrated in Figs. 7 and 8; this class may be called Broken point draws, because a new draw is begun before the other one is complete. Fig. 9 also comes in this class and represents a zigzag draw on 10 harness. [pg 10] [pg 11] The drawing-in drafts which we have described under the head of "Point draws," are used mostly to obtain the various pointed and zigzag effects. SECTION DRAWS Fig. 10 Fig. 11 Fig. 12 Fig. 13 Fig. 14 [pg 12] [pg 13] Fig. 15 This division of drawing-in drafts is used extensively in silk manufacturing; for instance, in all fabrics having a ground warp and a binder warp, also in double-face goods, or where two different weaves are combined in one effect. One or more threads are drawn on the first section, then one or more on a second and third, if the harness is divided in so many sets. The following examples will illustrate the principle of these draws. In Fig. 10, shafts 1, 2, 3, 4 from the first set, shafts 5 and 6 the second, 8 threads are drawn straight on the first, then 2 on the second section. Fig. 11, first set shafts 1 to 6 inclusive, second set shafts 7 and 8. Fig. 12 is drawn end and end on two sections having 8 shafts each. Figs. 13, 14 and 15, while not strictly belonging to the class of section draws, may, however, be considered under this heading. The idea is to draw a certain number of ends in one part of the harness and another group in another part, be it straight, point or skip, which will cause the effect on the cloth to be accordingly transposed or broken up. THE WEAVES AND THEIR CONSTRUCTION In any woven fabric we distinguish two systems of threads, the Warp or Chain, running lengthways in the cloth, and the Filling or Weft, crossing the former at right angles. This crossing or interlacing consists of every individual warp-thread being placed alternately under and over one or more threads of the filling system. The arrangement of this interlacing is technically called the Weave, and the variety in which the points of crossing can be distributed is practically endless. It is principally the weave that lends to a fabric its character, influenced, of course, by the material used, the size and tension of the threads and the combination of the colors. The weaves are divided into three main classes: the Foundation weaves. In the silk business they are known under the following names: The Taffeta Weave, The Serge Weave, The Satin Weave. In the foundation weaves each thread effects only one crossing in one repeat of the weave, and the points of interlacing occur in a given rotation. A repeat in the foundation weaves comprises the same number of warp-threads as of picks or filling threads, and if this number is 8, for instance, the weave is called an 8-shaft or an 8-harness weave. In marking out a weave, the warp-threads are represented by vertical lines, the filling by horizontal ones, or in each case by the space between these lines. The places where a warp-thread lies over the filling are marked with paint or simply with a cross. In a similar manner we mark out the chain draft, which indicates the rotation in which the shafts are raised. THE TAFFETA WEAVE [pg 15] [pg 16] [pg 17] Fig. 16 Fig. 17 This is the simplest and oldest method of interlacing. The odd numbers of warp-threads cross the even numbers after every pick; hence of two warp-threads one will always go over the first pick and under the second, and the other end under the first and over the second pick. Taffeta cloth, therefore, has the same appearance on both sides, and in cotton and wool weaving this weave is technically—and properly indeed—called the Plain Weave. It has the smallest repeat, 2 warp-threads and 2 picks, and the exchanging of warp and filling is the most frequent possible. The cloth thus produced is firmer and stronger than that obtained with any other weave. Fig. 16 is a taffeta on 4 shafts straight draw, the draft executed in the manner which we have already mentioned in explaining the drawing-in drafts. Fig. 17 on common designing paper, illustrates a taffeta made on 8-harness, skip draw. Be it mentioned that the drawing-in draft and the chain draft will be added throughout this work, the former over the weave to correspond with the respective warp-threads, the latter to the right of the drawing-in draft. GROS DE TOURS WEAVES [pg 18] [pg 19] Fig. 18 Fig. 19 In this weave the working of the warp is the same as in taffeta, except that instead of one pick, two or more are inserted in the same shed. It is mostly used in selvedges, where it serves to give more firmness to the edge of an otherwise loosely woven cloth, and prevents the weaving ahead of the edge in a tight weave. Gros de Tours is sometimes used, especially when cotton or wool filling is employed, with a view to lay two picks nicely side by side, whereas a thread entered two ply with the taffeta weave will always receive some twist, which may disturb the perfect evenness of the fabric. Fig. 18 is a Gros de Tours with two picks on four harness straight through. Fig. 19 illustrates this weave with three picks drawn end and end on two sections of four shafts each. SERGE or TWILL WEAVES While the taffeta weave produces either an entirely smooth fabric, or one with a distinct transverse rib as in gros-grain, the twill weave forms diagonal lines on the cloth, running either from left to right or from right to left. To make a twill, not less than three ends and three picks are required, of which each thread floats over two of the other system and interlaces with the third. The rotation of the interlacing is always consecutive, that is it moves with each succeeding pick one thread to the right (or to the left if the lines are to run in that direction). If warp and filling have the same texture, that is the same number of threads in a given space, the twill lines will form an angle of 45°; if the warp stands closer than the filling, the incline will be steeper, and in the opposite case the angle will approach more the horizontal. The weaves can be expressed in numbers, for instance: the 3-end twill warp effect would be marked 2-1, which indicates that each warp-thread goes over two and under one pick. Twill weaves are called evensided when the arrangement of "warp up" and "filling up" are evenly balanced, and unevensided if either warp or filling predominate on the face of the fabric; the latter class is therefore subdivided in Warp effects and Filling effects. In the following a number of serge weaves are illustrated, the French designations being added in some cases, as they are still extensively used in the trade. FILLING EFFECTS Satin de Lyon, 2-1. On 6 harness straight through. [pg 20] [pg 21] Fig. 20 Levantine, 3-1 On 8 shafts skip draw. Fig. 21 Polonaise, 5-1 On 12 harness skip draw. Fig. 22 Serge grosse côte, 7-1 On 8 shafts straight through. [pg 22] Fig. 23 Serge remaine, 6-2 On 8 shafts skip draw. Fig. 24 Serge, 5-1, 1-1. On 8 shafts skip draw. [pg 23] Fig. 25 Serge, 4-2, 1-1, 1-1. On 10 harness straight through. Fig. 26 Serge, 7-1, 1-1, 1-1, 1-1, 1-1. On 16 shafts skip draw. [pg 24] Fig. 27 WARP EFFECTS Levantine, 3-1. On 4 shafts straight through. Fig. 28 Serge, 5-1, 1-1. On 8 shafts skip draw. Fig. 29 [pg 25] EVENSIDED TWILLS Surah, 2-2 On 4 shafts straight through. Fig. 30 Croise, 3-3, 2-2, 1-1. On 12 shafts straight through. Fig. 31 Serge, 7-7, 1-1, 1-1, 1-1 On 20 shafts skip draw. [pg 26] [pg 27] Fig. 32 POINTED TWILLS in the direction of the filling and also of the warp. Fig. 33 On 4 shafts point draw, weave 3-1. Fig. 34 On 6 shafts point draw, drawn as follows: [pg 28] Eighteen ends from back to front and 4 ends from front to rear, weave 5-1. Fig. 35 On 8 shafts pointed draw, weave 5-1, 1-1. Fig. 36 On 10 shafts, with weave 3-3, drawn as follows: 7 threads fromback to front. 3 " " front to rear. 6 " " back to front. 2 " " front to rear. [pg 29]