Spinning is usually effected upon the cap frame (see fig. 6)—a frame in which the bobbin, resting upon a fixed spindle, is itself driven at say 5,000 revolutions per minute to put in the twist, while the friction of the yarn on the cap which covers the bobbin, or air-friction, enables the bobbin to wind up upon itself the yarn as delivered by the front rollers. The weakness and the strength of the cap frame is that to make reasonably hard bobbins the bobbins must be driven at a high speed.
The French are noted for a special system of worsted spinning, which, producing soft bot any yarns of a marked type, is worthy of more than passing com ment. The preparation is very similar to the preparation of botany yarns for the English system save that as a rule the order of the operations are carding, gilling, combing, back-washing and finish ing. The characteristic features of the method lie in the subse quent drawing and spinning. The drawing-box as shown in fig. 7 consists of back rollers, porcupine or revolving gill, front rollers, rubbers and winding-up arrangement. Thus there is no twist inserted, the slivers being treated softly and openly right away through the processes. A set of this type usually consists of two gill-boxes, preparing for combing, comb, back-washing machine and two finishing gill-boxes, first drawing frame, second and third drawing frame, the slubbing frame, the roving frame and the self acting mule. After leaving the last box as a fine soft pith-like sliver, spinning is effected upon the worsted mule. The main dif ferences between the worsted and the woollen mule are firstly, the worsted mule is fitted with preliminary drafting rollers, and secondly, there is little or no spindle draft, the worsted spindle being tapered as against thick-ended in the woollen mule. As the mule is an intermittent worker it is natural to contrast it with the cap frame, which runs continuously. What the real advantage is it is difficult to say, but the mule-spun worsted yarn trade is becoming yearly of more importance. The French-treated slivers are "dry-combed," no oil being employed. Normal English slivers contain from 3% to 5% of oil.
Upon whichever system the yarns have been spun it will frequently be necessary to twofold them and sometimes to three- and fourfold them. Again the fashion sometimes runs upon fancy twists, and then it is necessary to be able to produce the various styles of cloud, loop, curl, knop, etc.,
yarns. Twofolding is done upon the flyer, cap and ring frames. The main difference between the cap and the ring frame is that in the latter a small bent piece of wire, termed a traveller, revolved round a ring by the pull of the spindle through the yarn, serves as the retarder to enable the bobbin to wind the yarn, delivered by the front rollers. (See fig. 8.) Fancy twisters are almost univer sally on the ring system.
Yarns are placed on the market in eight forms, viz., in hank, on spools, on paper tubes, on bobbins, on ceps, in cheeses, in the warp ball form and dressed upon the loom beam. Thus the manu facturer can order the yarn which he requires in the form best suited to his purpose.
Although in some few cases special means must be employed for the weaving of woollens, worsteds and stuff goods, still the main principles are the same for all classes of goods. (See WEAVING.) Worsted cloth finishing is very similar to woollen cloth finish ing save that some of the operations are less severe. Mending, scouring, milling and tentering are similar. The raising as a rule is effected by brushing, although it is by no means un common to raise worsteds on the gig. Cropping, crabbing, press ing and steaming are the same as for woollen fabrics. Of course the real difference between the woollen and the worsted cloth is due to the selection of the right material, to correct roving, spin ning and fabric structure : finishing simply comes as a "developer" in the case of the woollen fabric, while in the case of the typical worsted fabric it simply serves as a "clearer," the cloth really being made in the loom. A woollen cloth as it leaves the loom is unsightly and in a sense may be said to be made in the finishing, although it is truer to say "developed" in the finishing : in the case of the worsted cloth it is altogether otherwise.
The principal styles of worsted cloths are coatings and trouser ings, delaines, voiles, merinos, cashmeres, lastings, crepe-de-chines, amazons, Orleans, lustres of various types (plain and figured), alpacas, Italians and moreens. Many are made entirely of worsted yarns, but others are compound so far as material or yarn is concerned. Thus amazons are made from mule-spun worsted warp and a woollen weft. (See also WOOLLEN MANUFACTURE.)