For the purpose of measuring the length of yarn on the beam, each warping frame is supplied with a roller half-a-yard in circumference, round which the yarn passes; on the end of this roller is a worm driving a worm wheel B, of 54 teeth; on the stud carrying B is a second worm C, driving a worm wheel of 132 teeth. The worm only takes one tooth at each revolution, therefore a complete revolution of the first worm wheel represents a length of 27 yards having passed the measuring roller; this is equal to one tooth only on the second wheel B; therefore, a complete revolution of the latter means 3564 yards—technically called a wrap—1/2 × (54 × 132)/(1 × 1) = 3564. If a warp contains 4 wraps and 7 teeth, it is 14,445 yards long - 4 × 3564 + (7 × 27). For other warping calculations see Chapter IX.
The faults in beams are principally, bad, or no piecings, soft places caused by fine threads, or ends unevenly distributed in the combs, or by crooked flanges.
Where dhooties and other striped cloths are made, the warper has to be provided with a sheet showing how the coloured yarn is “laid in” at the side. This will be described under the heading of Dhooties. Where possible, all the coloured yarn is placed on one beam of the set, leaving the other beams all “grey,” as the undyed yarn is termed.
In any case of warping two counts of yarn on one beam, whether coloured or grey, allowance must be made for the different diameters of the threads.
Sectional Warping.
PLATE III.—SECTIONAL WARPING FRAME. To face pp. 28 and 29.
Where a warp is composed of two or more different counts of yarn, or where a ball warp is required without having recourse to the old circular warping mill, it is usual to use a sectional warping frame—[Plate III].