What is Yarn Count?
Count is the linear density of yarn. The size of the yarn formed is, however, indicated as the ‘Count of’ Yarn or Filament. Thus, we specify ‘Hank’ of lap, sliver or roving whereas we specify ‘Count’ of carded or combed yarn, double yarn, fancy yarn or man-made filament. In this article I will give different examples of yarn count calculation.
There are two systems of Yarn Numbering / Count: (1) Direct System (mass per unit length) and (2) Indirect System (length per unit mass).
Example 1: Converting a yarn number:
Suppose, a yarn of ‘T’ Tex is to be converted to English count ‘Ne’ then by definition,
……………Tg
Tex = ———————
………..1000 m
………..T / 453.6 lb
= ————————————–
….1000 × 1.094 yards
…..T / 453.6 lb
= ——————————-
…..1094 yards
[Note: 1 m = 1.094 yards and 1 lb = 453.6 g]
This means that 1094 yards weigh T/453.6 lbs. Applying the definition of English count, we have to find number of 840 yards in lb. Hence,
………………………………………….1094 × 453.6
1lb of yarn will measure = —————————————— yards
…………………………………………………T
According to definition, therefore, number of 840 yard in (A) will give count (Ne)
………………………………………………1094 × 453.6
Number of 840 in 1 lb(Ne) = ———————————–
………………………………………………….T × 840
….590.7
= ————-
…….T
Instead of 590.7, the constant which is taken for the use is approximately 590
Thus we have, Ne = 590/Tex
Example 2: To derive the equation in a similar manner for Ne, Nf
If one metre length of lap weighs 300 g. Find the French count and English count.
One metre lap weighs 300 g, hence,
500 g of lap would measure = 500/300 × 1 = 1.66 m
By definition, Nf = 1.66/1000 = 0.00166 (French count)
Also, 300 g/m = [300 × 15.43] ÷ [ 1.094] grs / yd (Note 1 g = 15.43 grs)
= 4231.26 grs/yd
By using earlier expression (5), we can get English count.
Ne = 8.33 ÷ grs/yd = 8.33/4231.26 = 0.00196
[Note: Nf = 0.847 × Ne]
Example 3: A wrapping of six yards of card sliver gave the following readings–330 grs, 348 grs, 312 grs, 324 grs and 330 grs. What is the hank of the sliver?
The average weight of the wrapping is [330 + 348 + 312 + 324 + 330] / 6 = 55 grs/yd
By definition, 55 grs/yd means (7000)/55 yards in 1 lb.
Therefore, number of 840 yds in 1 lb will be: (7000) ÷ (55 × 840) = 0.151 Ne.
The same answer can also be obtained by using the constant 8.33. Thus,
Ne = 8.33/55 = 0.151
Example 4: The hank of roving is 0.8, find its weight in grains for a length of 15 yards.
By definition, 0.8 hank means number of 840 yards in 1 lb
Hence, (840 × 0.8) = 672 yards would weigh 1 lb or 7000 grains.
Therefore weight of 15 yards = [15] ÷ 672] x 7000 = 156.25 grains.
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