Yarn Spinning: Numbering

Yarn Numbering

Yarn numbering is a term used to describe a yarn’s physical size or, more specifically, its linear density.

Since short-staple spun yarns, like those containing cotton, can vary greatly in their bulk, measuring a yarn’s diameter, in a consistent way, can be almost impossible. For this reason, it is necessary to employ a more precise way of describing a yarn’s physical size.

Direct Yarn Numbering System

There are two main methods for assigning a yarn number. One method is called the direct yarn numbering system. In this method, the yarn’s linear density is denoted as a weight-to-length ratio. This method is commonly used for synthetic or man-made fiber.

For example, a 70 denier yarn means that there are 70 grams per 9000 meters. Denier is just one of the direct yarn numbering units but it is one of the more common direct units used for synthetics. Here are some others:

Direct Yarn Numbering Units:

• Decitex = weight in grams/ 10,000m
• Tex = weight in grams/1,000m
• Denier = weight in grams/9,000m

Indirect Method

The other method for describing a yarn’s linear density is called the indirect method. In this method, the yarn’s size is described in length to weight units. For cotton yarn, it is typical to see the denotations Ncc or sometimes Ne. These denotations are otherwise known as cotton count or number English. For example, a Ne 30/1 100% cotton or blend. Yarn means 30 times 840 yards per pound. 840 yards is known as a hank. There are also some other indirect units.

• Worsted Count = number of 560 yard lengths / Pound
• Woolen Run = number of 1600 yard lengths / Pound
• Woolen Cut = number of 300 yard lengths / Pound
• Number Metric (Nm) = number of 1000 meter lengths / Kilogram

With all this said it is important to realize that there are other yarn numbering units that may be encountered. It is impossible to cover all of them. This is especially true in China and some other foreign countries where many variations of yarn numbering may have evolved. Be aware that not everyone speaks or even knows all of these terms and their relationships.

Common Conversions

It is possible and often necessary to convert between the different yarn numbering systems in order to better communicate with your yarn supplier. Some common conversions include:

• Nm ÷ 1.69 = Ne
• 5315 ÷  Denier = Ne
• 590.6 ÷  Tex = Ne
• Denier ÷ 9 = Tex
• Decitex ÷ 10 = Tex
• Nw ÷ 1.5 = Ne

The above counts all represent ways to describe short-staple spun yarns. Short staple spun yarns can be made up of natural fibers which naturally grow to a staple length (such as cotton), synthetic filament fibers which have been cut to a staple length, or a blend of the two.

When describing yarns made up of filaments that have not been cut to a staple length, a yarn numbering system like this may be used:

2/150/34/1.25S/SB

• The first number represents the number of filament yarns plied together (in this case 2 filament yarns are plied together).
• The second number represents the linear density of each filament yarn in the ply (in this case each individual yarn has a size of 150 deniers).
• The third number represents the number of filaments in each filament yarn (in this case each yarn has 34 filaments).
• The fourth number represents the twist of the ply (in this case the ply twist is 1.25 turns per inch) and the direction of the ply (in this case the yarn is plied in the “S” direction).
• The fifth group of letters may represent the fiber luster (in this case the luster is Semi-Bright).