What Are the Main Standards of Yarn Quality?
Evenness refers to the amount of variations in mass per unit of a length of yarn. This characteristic can be seen with the naked eye and it is the first parameter to be measured when assessing the quality of yarn.
Complete evenness is almost impossible to achieve due to the nature of raw fiber.
Too much unevenness will cause weaknesses in the yarn and ultimately breakage will occur.
Yarn count refers to the thickness or fineness of a yarn. The yarn count is measured by wrapping the yarn around a rod. An inch of the wraps is measured out, then counted.
Knowing the yarn count is imperative to a hobbyist when choosing yarn for a project. The pattern or draft will dictate the size of yarn needed to produce the desired outcome.
Breaking strength or tensile strength measures the amount of pressure that is needed to break the yarn when pulled apart. Breaking strength is measured on a machine that clamps a length of yarn at each end and pulls.
Elongation is the amount of give a yarn has. A yarn that stretches before reaching the breaking point when pulled apart is a strong yarn.
A yarn that has a little give, is easier to work with and does not show minor mistakes.
Twist is what happens when yarn is spun. Twist holds the fibers together. The amount of twist determines the strength and overall quality of the yarn.
A well spun yarn must be balanced. If there is too much twist, the yarn will double back on itself and become useless. However, too little twist will make a weak yarn that will break when knitted or woven.
Yarn is spun in either direction to create a twist. Yarn spun in a clockwise direction is referred to as a z twist. Yarn that is spun counterclockwise has an s twist.
Two or more yarns can be plied, or spun, together to create a stronger yarn. When yarn is plied, it must be spun in the opposite direction that it was spun.