Four-thread overlock: how to choose and refuel?

The overlocker is very useful in sewing when you have to overcast the edges of fabrics, especially thin and loose ones. It is a highly specialized and at the same time advanced in capabilities machine that can perform many types of overcast, flat and rolled seams. The seams are made with an overlock, usually in 2, 3, 4 or 5 strands. In this article we will take a look at the last option - a four-thread overlock.

Since different types of overlockers perform different types of stitches, the 4-thread overlocker has its own application. Compared to the 3-thread, it has more advanced functionality and belongs to the category of semi-professional overlockers. On this type of machine, you can overcast edges in 3 or 4 threads, and the seam width is adjustable - you can adjust a narrow or wide stitch. Also on most models of 4-strand overlocks several flatlock seams are available in various widths.

The set of functions of this technique also includes a rolled seam (it is also called an undercut). Note that all of the above operations are basic, which should be supported by any budget overlock, but they are performed with a higher quality compared to a simple sewing machine. With the help of the latter, you will not be able to sew overlock seams, maximum overcast the edges with a zigzag.

The special functions of four-strand overlocks, for which they are usually bought, include working with loose fabrics, knitwear and elastic materials.This is already a more complex level of sewing work, compared to sewing simple fabrics and turning their edges. The four-thread overlocker also allows you to strengthen those parts of the product that will be exposed to more serious loads during use.

Thus, we recommend purchasing a four-strand overlock if your plans include working with the listed types of materials. Pay attention to the four-thread seams that a specific overlock model can perform, namely for what purposes they are performed and with what materials they are used. The main feature of the four-thread stitch is that in addition to the "base" of three threads, there is one more, reinforcing stitch from the fourth. This stitch plays an important role when you are working with stretch, stretch fabrics.

Four-thread overlock models can differ in the way they are threaded, feed the fabric, the number of settings and the sewing speed. Most modern high-quality four-strand overlockers have differential feed. This ensures a smooth advance of the fabric without jerking or stretching. Threading in the loopers can be manual or automatic (the price of the machine greatly depends on this), the same applies to adjusting the thread tension.

When choosing automatic or manual functions focus on your needs. If you have to perform a small number of sewing operations, and each of them does not imply a complex setting, you can get by with an overlock with manual threading and adjustment. In other cases, it is worth considering purchasing an automated machine - for example, advanced four-thread overlocks are equipped with an automatic threading system for the lower looper.

The process of threading an overlock is somewhat similar to threading a sewing machine, but at the same time it has significant differences. Note that The instructions below are for the common overlock class 51.

To thread the 4-strand overlocker, thread the threads through the holes in the thread guides on the machine body, and then thread them into the thread tensioner plate, as shown in the threading diagram in the instructions supplied with your model. The thread is then redirected to the needle and passed through the overlock foot. To check if the thread has been threaded correctly, it is recommended to sew a test stitch before starting work.

Overlock loopers are refueled separately... The location of the thread fasteners and tensioners in the loopers should also be checked according to the manual, these places may differ from model to model. Modern overlockers for threading loopers often have a color-coding system that greatly simplifies this process, or you can simply use different colors of thread.

Four-strand models have several distinctive features that are essential when refueling: the thread from the left needle is passed through the left tensioner, and from the right needle, respectively, through the right one. But the thread tensioners in the loopers are arranged in the opposite way.

After the threads are threaded into the overlock, you need to correctly adjust their tension, as well as the stitch sizes. Most models of overlockers have a disc with digital values ​​of thread tension (if the type of adjustment is manual). Integer values ​​allow you to approximately set the tension level; for more precise adjustment, half divisions are used. To understand whether to decrease or increase the tension, you need to look at the line. If wrinkles form on the fabric along it, you need to loosen the thread, if the stitches in the line resemble a ladder - on the contrary, increase it.

Thread tension is related to stitch length and stitch width adjustment. For most 4-thread seams, the correct stitch setting assumes a stitch length of 2.5-5 mm. With other sizes, you need to be careful so that there is no contraction, and, if necessary, compensate for this by tensioning the thread, as described above.

When dealing with various four-thread stitches, it is helpful to know some basic techniques. For example, when adjusting garments or patching parts of your garment, you may need to unseam the seams. When replacing old products, this generally takes a significant part of the work. Cutting the overlock seam with scissors or a razor is one option, but not the most convenient. You will have to cut a lot of thread and then remove the trimmings. It is better to open the seam first, and then unsewing and removal of most of the threads can be done much faster and easier.

To quickly loosen the threads of an overlock seam, take a closer look at it and find the top stitch - the one closest to the edge. It needs to be picked up with tweezers or a needle and pulled out, while loosening the threads of the other end of the seam.

Thus, the four-thread overlock as a semi-professional overcasting machine is well suited for overcasting most materials. It has many useful settings. Developers of modern models of such overlocks strive to bring the setup process to the most simplified standardized operations. In order not to waste extra effort when operating the overlock, it is recommended to purchase a machine with a convenient threading system (color-coded or with automatic looper threading).

Differential feed and sewing speed are also important in practice. High-speed models are considered, in which the last parameter is 1300-1500 stitches per minute. Finally, do not forget about such a simple but useful feature like backlighting. It is much more convenient to work with models that are equipped with LEDs. Based on the listed criteria, you can choose a four-thread overlock that suits you.

In the next video you will find an overview of the Jack JK-798D-4 four-strand overlocker.