The Changing of Solid Comber-boards for Different Textures.
In Jacquard work we generally use the same texture, or as near as possible, as the loom is tied up for; but changes are sometimes unavoidable. If we reduce the texture of the fabric in a Jacquard loom tied-up for a solid comber-board, we must reduce proportionally the number of hooks and needles used in designing, and hence the number of heddles used per inch. These heddles will thus be left empty when drawing in the warp. To accomplish this lift the full machine and throw the hooks not to be used from the knives, lowering in this way every mail which is not to be used. Sometimes there may be only one, two, three, or four hooks to be thrown off, on account of the design. At other times it may be necessary that one-eighth, or one-fourth, or even one-half of the whole number shall be dropped for this purpose. For instance, suppose we have a dressgoods design of 596 threads and a 600 machine. These four ends left off the 600, if in 6, 7, 8, or more inches in width, would not affect the fabric nor the cost to any great extent; hence we may leave out the first or last four needles of the 600.
Suppose we have a texture of 100 in the comber-board, to lower to 66 ends per inch. 66 ends, or the nearest even part of 100 (66-2/3) is 2/3 of 100; hence, we only need two-thirds of our machine; and as the same is supposed to be arranged 12 rows deep, we need 2/3 of 12 rows, or 8 rows. The four rows thus found necessary to drop may be dropped from the ends, or alternately, as follows:
Every alternate 2 rows taken, 1 row missed, 4 times over, = 12 rows. Or, 2 rows missed, 8 rows taken, 2 rows missed, = 12 rows.