Woolly Thread
What is woolly thread? It is a sewing thread made from synthetic filament thread that has been crimped and made bulky to increase stretch, softness, and covering performance.
Definition and Overview
Woolly thread is a bulky thread made by processing filament thread, primarily long fibers such as nylon, and adding fine crimp. It has loft, stretches easily when pulled, and produces soft seams.
In Japanese sewing workplaces, nylon processed thread is especially often called woolly thread or woolly nylon thread. On the other hand, it is sometimes used as a general term for textured thread without limiting the material.
Material and Twist/Structure
Typical woolly thread uses nylon filament and has a structure in which crimp is added through false-twist processing and similar methods. False-twist processing is a process that uses heat and twist to give the thread a memory of curl and crimp, creating stretch and loft in the thread.
Unlike ordinary sewing thread that keeps its shape with strong twist, woolly thread has an air layer created by fine loop-like or coil-like crimp. For this reason, it can soften seam feel and blend easily with the textile.
It is not a thread with rubber elasticity like polyurethane thread. Woolly thread’s elasticity mainly comes from the crimp stretching and contracting, so recovery and durability when pulled strongly must be checked depending on the material and processing conditions.
How Thickness Is Expressed
The thickness of woolly thread is shown by direct counts such as denier or tex, and may also be listed by a manufacturer’s own count designation. Direct count is a method that expresses mass per fixed length; the larger the number, the thicker the thread.
Because the reference for count designations may differ by product and manufacturer, thickness and suitability cannot be compared by the same number alone. When ordering, in addition to the stated count, check the material, thread construction, recommended needle and stitch type, and the actual loft.
Because the crimp creates apparent thickness, simply comparing counts with a smooth thread may result in seam volume and thread tension differing from expectations. In trial sewing, check both the finished seam and the seam under stretch.
Main Applications
Woolly thread is used for sewing products that need stretch and a softer feel against the skin. It is typically used as the looper thread in a lockstitch machine or overlock machine to create a soft seam that covers the seam allowance edge.
In innerwear, lingerie, swimwear, sportswear, knit products, and similar items, seams that follow fabric stretch are required. Using it for the looper thread that creates the seam surface, rather than the top needle thread, makes it easier to take advantage of its loft.
- Looper thread for lockstitch and overlock machines
- Finishing seam allowances for underwear and lingerie
- Sewing stretch materials such as swimwear and leotards
- Finishing seam allowances for cut-and-sew knits and knitwear
How to Choose and Sewing Precautions
Select the material and thickness according to the fabric’s stretch direction, thickness, and intended use. Nylon types can take advantage of softness and stretch, but the product’s washing conditions, heat resistance, and colorfastness should be checked in advance in combination with the textile.
Because it is bulky and tends to create friction, thread tension may not be stable with the same settings used for ordinary sewing thread. Check the threading path from the spool stand to the tension device, thread tension, feed, and needle condition, and always perform trial sewing on the machine and textile to be used.
There are also specifications that can be used for the needle thread, but friction at the needle eye and tension device may cause fuzzing, thread breakage, and skipped stitches. Check the product specifications to see whether it is for looper use only or also for needle thread, and set it up while avoiding excessive tension.
Frequently Asked Questions
What is the difference between woolly thread and ordinary sewing thread?
Ordinary sewing thread is relatively smooth and is generally designed with an emphasis on seam strength and stable sewing. Woolly thread differs in that it has loft and elasticity from its crimp, making it easier to finish seams in a softer, more expanded state.
Can woolly thread be used with a household sewing machine?
It can be used in some cases, but woolly thread is bulky, and depending on the machine and thread thickness, it may be difficult to achieve proper thread tension. First, test sew with a small amount and check whether it can be used for the needle thread, how it passes through the needle eye, the thread tension, and the seam stretch.
Is woolly thread the same as polyurethane thread?
No. Polyurethane thread is a thread with rubber-like elasticity, while woolly thread gains its stretch mainly from the crimp of the filament. Use them according to the required stretch, recovery, and sewing method.
