Most inexperienced needlewomen ask the question: “How to process the edge of the fabric without using an overlock and is the sewing line suitable for this?” If you need not only beautiful, but also high-quality trim - then you can not do without an additional device, and if you only learn how to work with fabric and train on old shreds, then for the start, the presence of only one machine will do.
The main difference between the machine and the overlock is that the first only imitates the line, and the second qualitatively completes the seam. This is easy to notice if you compare two samples of the seam: machine and overlock.
Choosing an overlock, it is necessary to fully study the functionality of the selected model and get acquainted with modern technologies for processing seams.
Features of the role seam
In the English transcription rolled, familiar to everyone role-playing seams (photo is in the article), mean "twisted, folded."
If you pay attention to the lines themselves and the technology of weaving threads, then this designation becomes quite understandable. Overlock role seam - what is it? A thin stitch with a minimum frequency of stitch , characterized by density, is called a role seam. The use of such a seam appeared as necessary, it is needed for those types of fabrics where the hem of the product edges is inappropriate due to the density of the material or other aspects that cause inconvenience during sewing.
Each of the specialized machines - overlocks - has a special tongue at the level of the needle plate, which occupies an intermediate position during the stitching: between the fabric and the thread of the upper looper. This technological design feature allows you to avoid twisting the edges of the product parts, adjusts the same width of the seam, provides a smooth stitch. If there is a need to overcast the product, remove this tongue, and the role seam on the overlock will work. In this case, the width of the seam will be minimal, and the edge of the product will be twisted into the stitched seam.
There are a number of subspecies of the basting, which is formed depending on the number of threads involved and their degree of interference.
Types of role seams
Several types of role seams are distinguished, which are divided by the number of threads involved during sewing:
- two-thread;
- three-strand;
- four-thread;
- five-strand.
Let us analyze all of the above types of role seams in more detail.
Double stitch seam
Modern overlock models for the most part perform processing using two threads. A two-thread role seam can also be made on a typewriter if it is equipped with a special converter that looks like a metal bracket worn over the upper looper. When a line is formed, the needle and thread of the lower looper are used in the work. The function of the upper is to transfer the lower thread to the needle, which contributes to the formation of the correct stitch.
The main advantage of this type of seam is its smaller volume compared to others.
The area of use is the processing of delicate and delicate fabrics.
Three-strand stitch
This type of seam is considered the most elementary. If you do not plan to continue to work in the clothing industry, you may well limit yourself to using a three-thread role seam for processing products. For its implementation, you will need a needle and a pair of loopers - levers with special holes in which threads are passed. With this device, the thread is fed over the fabric.
In fact, if you sew for yourself, it is not necessary to buy an overlock. Today you can buy several sets of paws, including overlock, and sew the same beautiful things as you like from the factory for your own pleasure. Sometimes hand-made things turn out better than goods from the store, and if you are a craftsman and you can cut, then it’s much cheaper.
Using a three-strand seam, sections are processed in products made from fabrics of various types.
Four thread stitch
An improved analogue of a three-stitch seam is a four-thread basting. When processing products according to this principle, needles (2) and lower loopers are used in the process. Outwardly, three- and four-strand seams are similar, the only difference is the additional line, which supplemented the second.
Feature - thinness and strength at the same time. Therefore, a role seam consisting of four threads is best suited for joining parts of products and simultaneously sewing them.
Five thread stitch
The five-thread stitch is called the classic sewing-overcast stitch. Most often it is used to process jeans trousers, therefore, turning such a product outward, you can familiarize yourself in detail with the principle of processing this type of seams.
The five-thread role seam combines three- and two-thread seams at the same time, between which there is a “chain” of overcasting at a selected distance.
Sewing is carried out during the operation of two needles and three loopers, one of which is presented in the form of a chain stitch lever.
With the help of such stitches, crumbling types of fabrics are most often processed.
The main feature is the simultaneous performance of two functions: turning and overcasting the edges of matter.
Overlock models that have entered the market one of the last can perform operations by working with ten threads simultaneously. In this way, the products are finished with decorative seams. The interwoven threads form various patterns, shapes and ornaments that give the item a twist.
Less common stitch patterns
Individual models of sewing machines can perform the function of both an overlock and a sewing system at the same time. Machines of this type are called "carpet".
An overlock role seam on the overlock (photo) with a rasping function is performed at the level of a special flat-seam mechanism.
You can sew in this way by equipping the machine with a special chain stitch looper. Models equipped with such a lever are much more expensive than usual, but they add functionality to the machines due to not only the seams described above, but also the stitches of the following types.
Single straight chain stitch stitch
Such stitches are used for sewing parts or sewing products made from soft, elastic fabrics. Two threads are used in combination: needle and thread, fed by a chain stitch looper.
The main advantage of stitches of this kind is elasticity. If necessary, the seam easily dissolves without damaging the fabric.
Two or three-line seams with flat stitches
The type of stitch and the number of threads involved is controlled by the number of needles installed in the carpet. On the front side, you get a flat and light flat stitch, and on the inside you get a quality overcast.
Such a role seam on the overlock (photo below) is most often used to process the bottom of products made from fabrics with the addition of elastin.
In the processing of sleeves of T-shirts and T-shirts from thin knitted fabric, flat role seams are used, which can be adjusted by adjusting the level of thread tension on the overlock.
Involving all three needles in the work, you can finish with a wide fling seam (when working with extreme needles).
When overlock is equipped with an additional thread-laying machine (upper), it becomes possible to process parts with a double-sided seam seam. The principle of operation of such a machine is to create an interesting decorative pattern on the front side instead of straight parallel lines. For the most part, this type of equipment performs from five types of flashing double-sided seams, but the cost of such machines corresponds to the declared functionality and not everyone can afford such a luxury.
Levels of thread tension when working with overlock
You have already familiarized yourself with all types of operations performed on the machine, due to the number of threads involved during the stitching. The degree of tension in this process is far from the last value. By adjusting the degree of tension of the threads, you can get stitches that are different in appearance and quality. So, by choosing a certain regime of the onslaught of the thread, you can get lines of the following types:
- Standard flatlock role seam when using two or three-thread seam, with strong tension of the lower looper thread and lower needle thread tension. When starting a fabric folded in two layers using such a seam, you can easily deploy them by noticing a flat lowercase seam at the turn. The role seam flatlock is conventionally called a flat seam, although its effect is more reminiscent of a stitch seam, due to which the overlay acquires decorative significance.
- Two or three strand flatlock seam.
- Narrow and wide flatlock overlock seams.
Mechanisms in an overlock
After a detailed description of the types of seams and the features of working with tensioners, you can begin to familiarize yourself with the special mechanisms that the machine is equipped to increase its functionality.
Differential conveyor
Thanks to this device, the fabric is protected from deformation during sewing. The conveyor consists of combs, of which there are two in the device: one in front of the needle, the second behind it. They, being in motion, smoothly move tissue without subjecting it to mechanical damage.
A differential conveyor is also used to create various decorative effects on fabrics, such as assemblies or waves.
Thread tensioners
One of the most difficult stages of controlling a sewing machine is the adjustment of thread tension and threading loops. Using such a mechanism, you still have to understand the essence of the action and adjust the role seam. Overlock in a modernized version is already equipped with a special looper refueling system, and earlier, it was necessary to cope with this troublesome process manually, sorting out the thread direction patterns and the threading sequence.
The degree of tension of the threads is adjusted using a special lever or wheel. In expensive models of new generation overlocks, a system for automatically adjusting the thread tension is installed, depending on the seam or stitch used in the work, but at the same time, the function of manual adjustment of the mechanism is preserved.
In budget models, voltage regulators (wheels) are located on a plane or on one of the axes. It is believed that a uniformly distributed tension between all the threads involved in the sewing process when operating at high speeds is achieved when the levers are located on the same axis.
Additional functionality
The useful functions of the overlock described above do not end there. In addition to the main ones, the device can be equipped with additional devices to expand the functionality, for example, paws, legs, designed to cut the threads, work with decorative elements. You can purchase a sleeve platform for high-quality tailoring of product details. As you can see, the role seam, the photo and features of which we studied, is not the only thing that can be done with this machine.
Having a certain store of knowledge about overlocks, as well as having decided on a direction for sewing, you can safely go to monitor market offers. Analyzing the prices, functionality and quality of machines, you can choose exactly the model of the mechanism that you need.