Taking the value as 25·6, this is divided by 1·25 = 20·4 cut woollen.
Sufficient has been given to show that it is comparatively easy to calculate counts of yarns regularly coming into the yarn store where we have a few standard hank lengths to consider along with the values obtained for each type of calculation met with in practice. Tables in each can be constructed from which the counts of yarn may be seen at a glance, the only work being to find the weight of the test length.
Yarn Conversion.—When two or more yarn classes are used in the same garment it is necessary for purposes of calculation to translate the counts into one or other of the systems, the most common system for choice. Thus, in cotton and wool, or silk and wool twist yarns, it may be necessary to make a calculation for counts and this cannot be affected unless both yarns are in the same denomination. The rule is to multiply the given counts by its own hank length and divide by the hank length of the yarn required.
Example 7.—Change 2/40's merino counts into worsted and Yorkshire skeins. 2/40's merino = 20's single, and by the rule—
| 20 × 840 | |
| = 30's worsted. | |
| 560 |
To convert into skeins counts the hank length is 256, and the formula is given by—
| 20 × 840 | |
| = 65·6 skeins. | |
| 256 |
Example 8.—Change 24/24 Scotch woollen into Alloa and skein systems. 24/24 = 12 cut single.
| 12 × 200 | |
| = 10's counts Alloa. | |
| 240 | |
| 12 × 200 | |
| = 9·4 skeins counts. | |
| 256 |
Example 9.—Find the equivalent of 40/2 spun silk in worsted and skeins counts. In silk the number is always the exact counts whether it be folded two or more ply. Thus, we have it stated as—