How the thickness (count) of yarns is determined
Many people ask me what 3×2/15, or 2/28 or 4600 means. This is the yarn count, i.e., the thickness. In this article, I want to try to explain exactly what it means and why.
Let's start by introducing the main characteristics of yarns.
The fundamental characteristics of yarns are twist or ply, thickness uniformity, strength and elongation, and count or thickness.
The twist of yarns is determined in twist testers.
The twist can be right (Z) or left (S).
Yarns are called single ply when they consist of a single strand or plied when they are formed by twisting multiple strands (or plies).
Thickness uniformity can be observed by winding a yarn onto a piece of cardboard of a different color than the yarn. The eye can detect any differences in thickness.
Strength is determined with dynamometers, devices that allow establishing the yarn's resistance before breaking and its elasticity.
Let's look in detail at the thickness or, in jargon, the "yarn count".
The "yarn count" is the conventional name referring to the fineness, i.e., the thickness of the yarn.
The structure of the yarn is typically cylindrical, so we might consider using diameter as a reference to measure its thickness. However, a yarn presents an inconvenience that makes it impossible to use a measuring instrument (such as a caliper); this has led to the need to think of another type of reference. The only two measurements that can be made on a yarn are those related to its length (L) and its weight (P); the ratio between these two quantities is called the Yarn Count (T).
There are two yarn count systems:
1.Count by length: Represents the ratio between length and weight. In this system, the higher the count, the finer the yarn. For example, a Nm. 4000 count will be finer than an Nm. 2000 count, and a 2/60000 count will be finer than a 2/28000 count. The metric count (Nm) belongs to this counting system, which is the number of 1000-meter skeins constituting 1 kg. It is used particularly for wool.
For cotton, the English count is used, which considers a length of 840 yards (equal to 768 meters) and a pound (equal to 453.6 grams). For linen, hemp, and jute, the English method is based on 300 yards (247 meters) and one pound.
LT = ——P
This is currently the most used method, it is the method you will find on the counts of our yarns, and it is the most widespread and known method in Italy, which I advise you to refer to most and learn.
To simplify the calculation, in the measurement of Nm. counts, we know that Nm 2000 corresponds to a yarn whose length is 2000 meters in 1 kg of yarn. While in the counts of plied yarns, we divide the denominator by the numerator. For example, in a 2/28000 count yarn, to obtain the meters of yarn contained in 1 kg, we divide: 28000 : 2 = 14000 meters in one kg of yarn, from which it is easy to obtain the meters in a ball or a skein, for example, of 100 grams.
The yarn count can also give us indications for determining the fineness of the machine or the number of needles to use for processing.
We know, for example, that a 2/28000 count yarn can be used on a 12 gauge machine with one ply or on a 7-8 gauge machine with two plies, or with 2.5/3 needles with two or three plies, and an Nm 2800 yarn can be worked with 3.5-4 needles or a 3-3.5 crochet hook. But this is relative, as the type of yarn (fiber) used, the model to be made, and for machine yarns the type of machine, and for knitting yarns the hand of the person making the garment, must always be considered. 2.Count by weight: Represents the ratio between weight and length. In this case, the higher the count, the greater the thickness of the yarn. With this counting method, we have the legal count, expressed in denier (0.05 grams) and a length of 450 meters. It is used for silk and all artificial and synthetic fibers.
PT = ——L
The count always refers to single yarns; in plied yarns, the count is expressed as a fraction (e.g., 30/2, 50/2, 60/3, etc.)
Similarly, there are different numbering systems that vary based on the units of measure being related. The most commonly used numbers are Nm (Metric Number), which relates 1 meter of yarn to 1 gram, which we have already discussed; Nec (English Cotton Number); Nel (English Linen Number); Np (Prato Number).
Tex should represent the universal count to indicate the thickness of yarns, but in reality, this is not always the case (it is useful, however, for production calculations).
Td is particularly used for silk yarns, technological fibers, or single fibers in general.
Np is used for counting carded wool yarns (only used in Prato).
The count of plied yarns with threads of different counts (flamed yarns) is expressed by indicating the count of the thickest yarn in the numerator and the count of the thinnest yarn in the denominator.
