This may be stated in a formula as follows:—
7000 × yards weighed840 × counts = weight in grains.
Staub’s Yarn Balance is a small balance which is made to test the counts of very small quantities of yarn. A template is given with the balance, and the yarn is cut into lengths the size of the template, about two inches. One end of the balance is slightly heavier than the other, and the number of threads the size of the template which are required to draw the balance indicate the counts of the yarn. If twenty threads or about 40 inches balance the small weight, the count of the yarn is 20’s, and so on.
The principle is the same as if a 1 lb. weight were put on one end of a balance, in which case the number of hanks required to draw the weight would indicate the counts, because if 20 hanks = 1 lb. the counts are 20’s, and if 21 hanks = 1 lb. the counts are 21’s. The balance may be made to weigh any length, according to the weight on one end of the balance.
The form in which it is usually made makes it specially suitable for testing the counts in small patterns of a few inches.
The test is, of course, only approximate, as could only be expected from weighing so short a length.
If the foregoing examples are thoroughly understood, the following will not be found difficult.
If a warp has 2000 ends, and is 500 yards long, and weighs 60 lbs., what counts is it?
The ends multiplied by the length will give the total length of yarn in the warp, and this divided by 840 will give the hanks. If the hanks are divided by the weight, the result will be the counts. The result may be obtained at once as follows:—
2000 × 500840 × 60 = 19·84 counts.