Count Systems:

Direct Count Systems

The direct systems are based on the weight or mass per unit length of yarn. Some typical direct systems are given below, together with their definitions. Please note that while the weight unit is gram, different lengths are used in the definitions.

Tex (g/1000m)

This is the mass in gram of one kilometre, or 1,000 metres, of the product.

If one thousand meters of yarn weigh 20 grams or one hundred meters of the yarn weigh 2 grams, the yarn would be 20 tex. On the other hand, if 100 metres of yarn weigh 5 grams, then the count of the yarn will be 50 tex.

Dtex (g/10,000m)

This is called deci-tex. It is the mass in gram of ten kilometre, or 10,000 metres, of the product. It is a smaller unit than tex (1 tex = 10 dtex), and is usually used for fibres and filament yarns.

A 167 dtex polyester filament would weigh 167 grams for every 10,000 meters of the filament.

Ktex (g/m)

This is called kilo-tex. It is the mass in gram of one metre of the product. It is a much larger unit than tex (1 ktex = 1,000 tex), and is usually used for heavy products such as slivers.

If a sliver weighs 5 grams per metre, then the count of this sliver would be 5 ktex.

The tex system (tex, ktex, dtex) is the preferred standard system. By definition,

            1 ktex = 1,000 tex = 10,000 dtex

Denier (g/9,000m)

Denier is also used extensively in the industry, particularly for manufactured fibres and silk. It is the mass in gram of nine kilometres, or 9,000 metres, of the product.

By definition,

            1 dtex = 0.9 denier

If a 300 denier yarn is made up of 1.5 denier individual filaments, there will be a total number of  300/1.5=200filaments in the yarn.

Indirect Count Systems

Indirect count systems are not as straightforward as the direct ones. In the early history of yarn manufacture, different spinners, often geographically and culturally isolated from one another, devised their own ways of measuring yarn thickness. Consequently, there are numerous indirect count systems that have been, and continue to be, used in the industry. Some examples are given below, together with the mass and length conversions,

Commonly used

- Metric (N_m)                          m/g

- English Cotton (N_ec)            No. of 840 yard hanks per pound

- Worsted (N_w)                       No. of 560 yard hanks per pound

The metric count (Nm) is relatively straightforward. It is the length in metre of one gram of the product. For example, if one gram of yarn measures 40 metres, then the metric count of this yarn would be 40 Nm.

Similarly, if one pound of cotton yarn measures 1,680 yards, or two hanks of 840 yards, the English cotton count of this yarn will be 2 N_ec.  Please note that a hank of yarn is an unsupported coil consisting of wraps of yarn of a certain length.

The conversions between different units will be discussed later.

Less commonly used

- linen, hemp, ramie                 No. of 300 yard hanks per pound

- asbestos                                 "   "   50  "     "    "    "

- glass                                      "   "  100  "     "    "    "

- spun silk                                "   "  840  "     "    "    "

- raw silk (dunce)                    "   " 1000  "     "    "  ounce

  

Occasionally used in the woollen industry

- Yorkshire skein                     No. of 560 yard hanks per pound

- West of England                   "   "  320  "     "    "    "

- American cut                        "   "  300  "     "    "    "

- American run                        "   "  100  "     "    "  ounce

- Dewsbury                             "   "    1  "     "    "  ounce

- Galashiels                              "   "  300  "     "    "  24 ounces

You may wonder how the strange length units such as 840 yard hank and 560 yard hank came about. The first mass-production spinner – the spinning-jenny was able to spin yarns simultaneously onto several bobbins and filled the bobbins up at the same time. The bobbins were changed after 840 yards of cotton yarns were wound onto them. To estimate the thickness of the yarns, the spinner simply counted how many full bobbins were needed to balance a weight of one pound. For example, if 6 bobbins were needed to make up one pound, the yarn would be called a 6s yarn. Similarly a 20s worsted yarn means one pound of this yarn would fill up 20 bobbins, each with 560 yards of yarn wound on.

Conversion between Different Yarn Counts

It is often necessary to make conversions between different yarn count systems. For this purpose, the following mass (weight) and length conversions are needed:

1 yard (yd)      = 0.9144          m        

1 pound (lb)    = 0.4536          kg

1 ounce (oz)    = 1/16              lb

1 dram 9dr)     = 1/16              oz

1 grain (gr)      = 1/7000          lb

Worked Examples

Question:

What is the conversion factor between worsted count (Nw) and tex ?

Solution:

According to definition, one worsted count (Nw) = one 560 yard hank per pound, or

1 Nw= (1 x 560 Yard/ pound)

Since 1 yard (yd) = 0.9144 m and  1 pound (lb) = 0.4536 kg, the above equation becomes,

1 Nw= {(1 x 560 x 0.9144m)/453.6g}=512.064m/453.6g= 1.12892m/g

Therefore, for a yarn of Nw worsted count, each gram of this yarn would measure 1.12892 times Nw meters. Since tex is the mass in gram of a 1,000 meters of yarn, we need the number of grams in 1000 m of the yarn.

No. of grams per 1000 m(Tex)= 1000/(1.12892 xNw) = 885.8/Nw

The above equation can also be written as: Nw=885.8/Tex

So the conversion factor is 885.5.

Question:

If a yarn is 20 tex, what is the worsted count of this yarn?

Answer:

Using the conversion factor given above, the worsted yarn count is 8858/20=44.3Nw.

Conversion between other count systems can be worked out in a similar way. Table 1.1 lists commonly used conversion factors. You may try to work them out yourself.

Table 1.1: Factors for Yarn Count Conversion

	DIRECT COUNT		INDIRECT COUNT
	To Tex	To Denier	To Metric Count (Nm)	To Cotton count (Nec)	To Worsted Count (Nw)
From Tex		9x Tex	1000/tex	590.5/Tex	885.8/Tex
From Denier	0.111x denier		9000/denier	5135/Denier	7972/Denier
From Metric count (Nm)	1000/Nm	9000/Nm		0.59.5x Nm	0.8858xNm
From Cotton count (Nec)	590.5/Nec	5135/Ne	1.693x Nec		1.5xNec
From Worsted count (Nw)	885.8/Nw	7972/Nw	1.129xNw1.	0.666x Nw