(157) In clothing the various parts of the machine experience has shown that there can be wise variations made in the kind used. Every spinner has ideas of his own, and as there is a wide difference in the class of material treated no rule can be laid down. In clothing the licker-in, a tooth which is known as the “Garnett” is universally used. An illustration of this is given, in full size, in Fig. 77, the finer tooth shown being used when no undercasings are fitted, and the coarser when they are. It will be noticed that the former is a little more hooked than the latter, which enables it to carry round the cotton without flinging it below the licker-in. The presence of an undercasing obviates much of the necessity for this carrying power, and the tooth is only required to beat off the cotton from the lap and thus throw down the motes, etc. In covering the cylinders of roller carding engines, where medium counts of yarn are being spun, clothing with 90’s to 100’s wire is used, the rollers being covered with the same counts, the clearers with a finer wire, and the doffers from 100’s to 120’s. These, of course, are sizes which are commonly employed, and indicate the usual limits, but, as has been observed, practice varies considerably in this respect. In revolving flat carding engines the cylinders are covered with 110’s, and doffers and flats with 120’s for medium counts of yarn. It may be generally stated that the finer the counts of yarn spun, all other things being equal, the finer the wire clothing employed; but it can only be settled by practice what are the best counts to use in any individual case.
(158) As has been observed, the wires are, in the process of setting, bent to an angle, or, rather, a double angle, after leaving the foundation. A reference to Fig. 85 will show that they leave the foundation at an angle in one direction, and afterwards bend sharply in the opposite direction. The diagram given in Fig. 78 illustrates this construction. The foundation is shown by the letter =D=, to which the line =A B= is perpendicular, leaving the upper surface of =D= at =E=. The tooth is indicated by the line =A C E B^{ 1}=, and it will be noticed that the point of the tooth at =A= is perpendicular to the point =E= where it leaves the foundation. This is the correct setting, or nearly so, for the following reason. Some makers, it may be stated, prefer to let the point =A= be a little behind the perpendicular line =A E=. In working, the wire point is pressed by the material and is sprung backward, in which case it—when set as shown—will radiate round =E= and move in the circle shown by the letters =F A G=. Thus, if another set of wire points are imposed upon the lower ones, the flexure of the latter, in either direction, is followed by their recession from the former, and no danger exists of any interlocking, which, if it occurs, is injurious to both sets of teeth. As the relative positions of the upper and lower teeth are of the character described in the previous chapter, the adoption of the method of setting the teeth indicated is of considerable importance. It is, of course, possible to vary the angularity or “keen” as desired, and the more acute the angle =E C A= the more fibre caught and retained. Thus the proportion of waste made in a machine during work is largely dependent on the angular setting of the wires, and this is a point specially worth noting. The essential element is the approximate perpendicularity of the point =A= of the wire to that (=E=) where it leaves the foundation.