The last type, the Noble, is the most popular of all and, by a change of large and small circles, may be adapted to the combing of long, medium or short wools. As the great bulk of cross-bred and a considerable proportion of botany wool is combed upon the Noble comb a brief description is here called for. The object of all wool combing is to straighten the long fibres and to comb out from the slivers treated all the fibres under a certain length, leav ing the long fibres or "top" to form the sliver which is eventually spun into the worsted yarn. The Noble comb, which so effectually accomplishes this, consists in the main of a large revolving pinned circle A inside which revolve two smaller pinned circles B, B' as shown in fig. 3, each of which touches the larger comb circle at one point only. At this point the slivers of wool to be combed are firmly dabbed into the pins of both the large and small circles. As the circles continue to revolve they naturally begin to separate, combing the wool fibres between them, the short fibres or "noil" being retained in the teeth of both small and large circles, the long fibres hanging on the inside of the large circle and on the outside of the small circle. A stroker or air blast at F now directs these long fibres towards the vertical rollers, G and G', shown here in plan, which separate them from the short fibres.
There are at least four pairs of drawing-off rollers in a comb, and the fibres drawn off by each—be it noted continuously—are united to form a sliver which is passed through a revolving funnel into a can. The short fibres, or "noil," are lifted out of the pins of the small circle by "noil knives." The continuous slivers, the ends of which remain in the pins of the large circle after the drawing-off rollers have been passed, are now lifted up until these ends are above the pins, at the same time an additional length of sliver being drawn into the comb, so that, as the slivers reach the second small circle, they are ready to be again dabbed into the pins of both circles and the combing operation is repeated. Thus the combing on a Noble comb is absolutely continuous. All the movements of this machine—with the exception of the dabbing brush motion—are circular, so that mechanically it is an almost perfect machine.
After combing it is usual to pass the "top" through two gill boxes termed "finishers." The last of these boxes, and often the first, delivers the "top" in the form of a ball, thus it is often spoken of as a "balling gill-box." This stage marks one of the great divisions of the worsted trade, the comber taking the wool up to this point, but now handing it 'forward in the shape of top to the "worsted spinner," who draws and spins the slivers into the most desirable worsted yarns.
The object of drawing is to obtain firstly a level sliver from which an even thread may be spun, and secondly to reduce the comparatively thick top down to a rela tively thin roving from which the required count of yarn may be spun. Of course par allelism of fibres must be retained through out, so far as possible. To accomplish these objects doubling and drafting is resorted to. Thus the ends put up at the back of the above boxes will be 6, 6, 4, 4, 3, 3, 2 re spectively, while the drafts may be 5, 6, 8, 8, 6, 9, 9 approximately. As the drafts markedly preponderate over the doublings so will the sliver be reduced in thickness.