In this blog post, we’ll explore how to compare and measure the thickness of threads that are too fine to measure easily with a ruler, using two methods: the “hangjang-sik” and “hangjung-sik.”
What are the methods for comparing thread thickness?
The tradition of celebrating a baby’s first birthday in a special way can be found in many parts of the world. Among these traditions is one where various symbolic objects are placed in front of the child, and the child’s choice is used to imaginatively predict their future life. Korea’s “Doljabi” is a prime example. During Doljabi, objects such as money, a book, a brush, and thread are placed in front of the child, and observers watch to see which one the child picks up. Each item carries a different meaning—such as wealth, scholarship, or longevity—and people often use the child’s choice to make playful predictions about their future life. In particular, because of its long, continuous nature, thread has long been regarded as a symbol of the wish for a long and healthy life. Thus, while thread represents the characteristic of being “long,” it is also very “thin.” This raises a question: If threads vary in thickness, how can we compare those differences? Using a ruler to measure them directly is impossible because ordinary thread is thinner than the smallest mark on the ruler. Therefore, determining the thickness of a thread requires a different method than the standard approach of directly measuring an object’s diameter. Consequently, when measuring the thickness of a thread, we use a method that differs slightly from common sense to gauge its thickness. The “constant-length method” and the “constant-weight method” are precisely such methods.
What is the constant-length method, which compares the thickness of threads while keeping their length constant?
What is the constant-length method? If we break down the Chinese characters, “恒” (constant), “長” (length), and “式” (method), it refers to a method used under conditions of equal length; it determines the thickness of a thread based on how much it weighs when cut to a fixed length. For yarns made from the same raw material, if one weighs more than another at the same length, it means more raw material is contained within a given volume. Therefore, according to the weight-per-length method, yarn with a higher value is thicker than yarn with a lower value. The units most commonly used for this method are denier and tex. Denier and tex are units that indicate how many grams (g) a given length of yarn weighs, with 9,000 meters and 1,000 meters serving as the respective reference lengths. Generally, linear density is used to describe the thickness of long fibers and yarns.
What is the “constant-weight method” for comparing the thickness of yarns while keeping the weight constant?
The constant-weight method is easier to understand. The term “constant-weight method” (恒重式)—where “constant” (恒) means “constant,” “weight” (重) means “weight,” and “method” (式) means “method”—refers to a method used to determine how thin a yarn is by comparing the lengths of yarns that have the same weight. Similarly, when threads of the same weight and raw material are compared, if one is longer, it must be arranged so that a smaller amount of raw material is stretched over the same length to achieve that greater length. Therefore, according to the constant-weight method, a thread with a higher value is thinner than one with a lower value. The unit used in the weight-per-length formula, “count,” is a term quite familiar to us. However, the type of count varies depending on the length used as the standard; in the British system, for example, it is based on yards (yard) and pounds (pound), and the standard unit length differs depending on whether the yarn is made of cotton or silk.
Since the yard and the pound are not international standard units, the use of the international common count (Nm), which is based on the meter (m), was recommended in the past; however, its usage is still relatively infrequent. The international common count is based on 1,000 grams and indicates how many thousand meters a given amount of yarn measures—that is, how many kilometers 1 kilogram of yarn measures. The weight count is primarily used to indicate the thickness of spun yarn.
Simply put, the length count and weight count compare yarn thickness by keeping one value fixed and varying the other. This may be difficult to grasp at first glance. Let’s think about it a bit more easily using an analogy. If we think of fibers as people and yarn as a line of people standing in a row, the number of threads per unit weight is like having a fixed length of space for people to stand in a line. The more people there are, the more they have to gather in two, three, or even more lines to fit within that space. In other words, the more people there are, the thicker the line becomes, which is equivalent to the value of the number of threads per unit weight increasing, making the yarn thicker. On the other hand, the constant-density method can be likened to a situation where a limited number of people are lining up. As more people gather, the line becomes shorter but denser. In other words, the lower the value in the constant-density method, the thicker the thread becomes.
Generally, when we need to measure thickness, we try to determine the diameter of an object. However, when we encounter a “thread” so thin that this is impossible, we find a solution by shifting our perspective—just as Columbus did when he first stood an egg upright on its end without breaking it. Beyond this, there are many problems—both big and small—in our daily lives that require solutions but for which it’s difficult to find a straightforward approach. Looking at situations from multiple angles and, at times, reversing our perspective might just provide the key to solving such problems.
