Do-it-yourself overlock repair of class 51

Overlock class 51 is the most common industrial overlock of the “Soviet” period. It was impossible to buy it in those days, but such overlocks were in every atelier, sewing workshop and even a sewing factory. Despite the fact that this overlock is from the “last” century, nevertheless, it is still often used at home, in small ateliers for tailoring and repairing clothes.
Morally, this sewing technique has long been outdated and many modern fabrics are simply impossible to overcast with high quality on it. However, using a grade 51 overlocker is sometimes justified, as it does a good job with fabrics such as denim, drape and even thin tarpaulin.

Affordable price is another advantage of this overlocker. The cost of a used overlock is an order of magnitude lower than the prices of modern overlock models, and even more so household overlocks. Especially, this difference is noticeable in comparison with the prices for industrial overlocks. For 3-4 thousand rubles, it is quite possible to buy such a used overlock, and a rather “decent” look.
Overlock class 51 has another advantage - reliability. This is a fairly reliable overlock, parts break extremely rarely, only sometimes it becomes necessary to perform minor repairs and adjust the overlock.

All instructions for the overlock class 51 have long been lost, or maybe they did not exist at all. There is practically no literature written in an understandable language, the services of a master will sometimes cost more than the overlock itself, and you need to set up the overlock. For such a case, we offer you our own small recommendations on how to set it up. overlock 51 class.

Class 51 has a unique feature - it can work using just two threads. Perhaps such “savings” are no longer relevant today, but you should know that if you put a spreader instead of one of the loopers, then the overlock will work “on two threads”. One is threaded into the needle, the other into the looper.

The maximum rotational speed of the main shaft is 3500 rpm;
Stitch length - 1.5. 4 mm;
Overcasting width - 3-6 mm;
The maximum thickness of processed fabrics is 2.5 mm.

Overlock class 51 is distinguished by the presence of a differential fabric feed (rails). The Class 51-A machine has a simple rail. It can be more simply explained like this. The 51 grade overlock rail can stretch the edge of the overcast fabric, which makes the seam elastic after overcasting. This is very important for finishing the edge of knitted fabrics and is indispensable for sewing sportswear, T-shirts, etc. Therefore, it can qualitatively overcast not only suit and coat fabrics, but also knitted, linen fabrics with a knitted weave of threads.
Outwardly, both overlocks are exactly the same, but the presence of a differential rail greatly increases the capabilities of one of them.

Both machines use short needles with a thickened flask. The marking of the needles indicated on the package should look like this: needle type - 0029, needle thickness - No. 60, 65, 75, 90, 100.

To set up the overlock on your own, one instruction is not enough; experience is required. The correct interaction of the loopers and the needle with each other occurs when many parameters are observed. It is quite difficult for an inexperienced “master” to set them exactly. Therefore, if you do not know how to do it, it is better not to try. Moreover, most of the defects in a bad stitch have other causes, such as incorrect thread tension, a dull or bent needle, poor-quality threads, etc.

In this manual for a class 51 overlocker, the basic parameters for setting the interaction of loopers and needles are given, which can only serve as a guideline for “rough” settings. “Fine” adjustment of the overlock is made taking into account many factors that have individual characteristics for each overlock. The general principle of setting up an overlock is as follows: all loopers and the “meeting” needle should have minimal gaps. The looper must “surely” enter the loop formed above the eye of the needle, the needle must securely enter the loop formed by the looper.

The main reference point when setting up a class 51 overlocker is the left looper (lower) L. When lowering the needle to its lowest position, it should take the leftmost position. The looper nose at this point should be 4.5 mm away from the needle.
When the needle is raised by 2.5-3 mm, a loop is formed just above the eye of the needle. The nose of the left looper, moving to the right to the needle, passing 1.5. 2 mm above the eye of the needle, should capture the resulting loop.
The gap between the looper blade and the needle should be as small as 0.05 mm. This gap can be set by loosening the left looper fixing screw B and carefully turning the looper as it approaches the needle. Do not loosen screw B too much, the looper should turn with little effort. Having achieved the required clearance after several attempts, do not forget to fix the mount (B).

Having grasped the needle loop, the left looper pulls it along its blade, and the right looper R is already moving towards it to enter the loop created by the left looper.
The nose of the right looper passes along the recess on the back of the left looper, as close as possible to its eye and blade at the same time.
If a horizontal line is drawn at this point, the nose of the right looper should be below the eye of the left looper and the gap between the blades of both loopers should be 0.1. 0.15 mm.
You can get confused in these terms and provisions, but it doesn’t get easier.
Now it remains for the needle to remove the loop from the right looper, and the overlock will work like a clock.

When the needle enters the loop of the right looper, the gap between the needle and the looper blade should also be 0.1. 0.15 mm, and the distance between the eye of the right looper and the point of the needle (when they are at the same level) is approximately 0.3..0.5 mm.
The right looper does not have an adjustment screw to bring its nose closer or further away, it is rigidly fixed with a screw to the platform. Its adjustment takes place in a banal way - by carefully bending in one direction or another. But the left looper cannot be bent like that.

It should be noted that there is only one correct position of the loopers and needle, in which a class 51 overlock will work flawlessly.

All of the above parameters are only a rough guide to overlock settings. It is possible that some parameters will be different for your machine, since a lot also depends on the installation of the cam.
Turning the cam 1-2 degrees will change the position of both loopers at the same time. Therefore, in order not to break the loopers when they meet, this adjustment should only be made by an experienced tuner.

The reason for the sudden appearance of gaps may be the displacement of the needle bar with the needle up, check this parameter first. Perhaps by simply lowering the needle bar (screw I) by 0.5-1.0 mm, you will eliminate gaps.
Sometimes, threads that are not suitable for overlocking can also cause gaps in the stitches to appear. See Sewing threads, which is better?.

Proper threading is the main condition for the normal operation of the sewing machine, this is especially important for overlock. Tweezers are used to thread the overlock loopers.

First, thread the right (upper looper R), (Fig. P). Through two holes 1, between the tensioner washers 6 into the thread feeder 8, under the bracket of the wire thread guide 9 and into the eyes of the looper away from you.From the stand, with the bobbin of the lower (left) looper L, the thread is threaded (Fig. L) into hole 1. Then into the eye of the thread take-up 3, and into the hole of the thread guide 8, located on the overlock cover. Then it is passed through the hole 9 and 10 in the side cover, then through the tensioner 12. It is passed through the tubular thread guide 13, under the thread puller 14 and into the eyes of the left looper away from you.
The thread of the needle from the rack from the bobbin is passed through the hole 1 in the thread guide plate 2, between the washers 3 of the tension regulator, the holes 4 on the left side of the plate 2 in front of the shaped thread take-up 5. Then into the eye 6 of the thread feeder, mounted on the leash of the needle mechanism, between the washers 7 into the eye of the needle 8 away from you.

The overall movement of the rack is controlled by an eccentric, which is adjusted by two screws located deep in the eccentric body. An eccentric is attached to the main shaft of the overlocker.
In body 1 there is a groove for the passage of a slider (eccentric 4) in it, the displacement of which leads to a change in the stitch length (more often, less often). This displacement is carried out by screw 2 after loosening screw 3.

Dull knives “tear” the edge of the fabric instead of cutting, which is often the cause of most stitching defects. Unfortunately, you cannot sharpen knives yourself. But, using this instruction, you can remove them and put them back. You need to sharpen knives on a special machine with fixing the sharpening angle. Contact the craftsmen who make the keys, they have such machines, but keep in mind that not everyone will undertake to sharpen overlock knives.

General recommendations for installing knives.
The lower knife should be flush with the needle plate. The upper knife should be firmly pressed against the lower knife with the entire cutting edge and lower (go in) beyond the edge of the lower knife by 1.0 -1.5 mm, no more.
Just in case, we provide fragments of the factory instructions. From the fifth attempt it will be easier to understand it.

Overlock 51 class can work on any thread. This is another feature and advantage of it. Even the old bobbins of cotton thread, preserved from Soviet times, are nothing to him. We have a whole box of such threads (given by one customer) and now half of the box has been recycled by our old overlocker of class 51. But still, he “likes” the large cone bobbins of number 35 more. Works great on threads like “Ideal” and other brands wound on small spools. It is only desirable to put threads of the same type and thickness on all loopers and the needle, although it is not necessary. Just adjust the stitching with the thread tensioner. Each type of thread has its own “resistance” and therefore, it is imperative to adjust the tension of each of them separately.
Incorrect tension on each individual thread sometimes causes gaps, not to mention the appearance of the stitch.

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Overlock Janome ArtStyle 4057
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Preventive maintenance, do-it-yourself overlock settings
You can and even need to be able to set up an overlock yourself. Overlock repair is needed only in cases where there is a “failure” of some nodes. Basically, all overlock problems “lie on the surface”. Incorrectly selected threads, blunt needle, incorrectly adjusted thread tension, etc.

Which overlocker to buy
Do you have 51 grades but would like to purchase a modern four-thread overlocker? Modern overlockers are capable of performing many types of overcasting seams, including various decorative stitches. They qualitatively overcast complex knitted fabrics, have a backlight, are light and beautiful. Use our recommendations, perhaps they will help you choose an overlock.

Which carpet to buy
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Do you have a sewing machine and love to sew? Then this site is for you. Professional masters will tell you how to carry out minor repairs to a sewing, knitting machine. Experienced technologists will share the secrets of tailoring. Review articles will tell you which sewing or knitting machine to buy, an iron mannequin and many other useful tips you will find on our website.
Thank you for viewing the page in its entirety.

Any overlock is much more complicated than a sewing machine. To configure many parameters of the operation of overlock units, moreover, only a master with special knowledge, skills and experience can repair mechanisms. It is almost impossible to make adjustments with your own hands, for example, the interaction of overlock loopers. However, it is not always necessary to repair or adjust its knots, sometimes it is enough to correctly adjust the thread tension and the overlock will again overcast the fabric with high quality.

Almost all overlocks, except for the old model of the industrial overlock of class 51, are very sensitive to thread tension, and when switching to other threads in thickness and quality, you have to adjust the tensioners. This is the most common cause of poor-quality overlock work. But there are other reasons, let's look at them.

First, let's figure out how the overlock stitch is formed.
An overlock stitch uses two loopers and a needle to form a stitch (three-thread stitch). In modern models of knitted overlocks, two needles are installed, due to this, the overlock performs a better four-thread overlock stitch.
When adjusting the thread tension in a stitch, it is important to understand which thread belongs to the needle(s) and which belongs to the loopers.

In this diagram, it is clearly seen that the needle thread (I) does not overcast, but grinds, but the looper threads (P) overcast the cut edge of the fabric. Moreover, the green thread (lower) belongs to the left looper, and the beige thread (top) belongs to the right looper.

Be sure to figure out which looper puts the lower thread and which upper thread. And remember which tensioner regulates each of them. Then, just by looking at the line, you will immediately understand which thread needs to be tightened and which should be loosened.
Most often, when a bad line appears, random rotation of all handles in a row begins, completely knocking down the tensioner setting. As a result, the overlock begins to skip and sometimes break the thread.
And yet, by learning how an overlock stitch is formed, you will get rid of the illusion that a sewing machine can perform an overlock stitch. The sewing machine can only imitate the overlock stitch, since it has a completely different stitch formation principle.

Some instructions provide for adjustment of the loopers, and give the parameters for setting them in relation to the needles in case of failure of these gaps or when replacing the loopers. As a rule, these parameters are indicative, so to speak ideal. The master who repairs overlocks has to experimentally bring them to the desired value, so this type of repair is recommended to be done by a professional.

All our recommendations in the overlock repair section are generalized, universal and suitable for any overlock model, but do not forget to carefully read the instructions for your model, where you can find information on setting up, lubricating, choosing the type of needle and more.

If you have gaps or a dull thud, then the needle is most likely blunt or bent. A dull needle can cause many problems. The overlock needle is a very important detail, many parameters depend on its condition, in particular, the clearance of the needle with the looper is the main parameter for performing overlock stitching without gaps.

A blunt needle can be identified by running the thumbnail along the tip of the needle from all sides. The nail will definitely find a bent place on the tip. You can use a magnifying glass to inspect the point of the needle.

If the needle is bent, do not try to straighten it, the overlock settings are very precise and do not use such needles.
A bent needle or not can be determined by placing it on a flat surface. Inspect the needle from above and from the side: 1 - parallel clearance; 2 - flat surface (glass, etc.)

Pay special attention to what type of needle is installed in the overlocker. It is imperative to follow the requirement of the manufacturer's instructions - to use the types and brands of needles recommended by the factory.
In addition to the fact that needles can be with a round or sawn bulb, they can also differ in the length and thickness of the bulb, the length of the needle itself, and other parameters.
If the overlock uses needles with a round flask (class 51 overlock), you need to replace with a needle with the same thickness and length of the flask.
See Sewing machine needles.

The sizes and types of needles used are indicated in the instructions, sometimes their brands are indicated on a sticker located on the inner surface of the hinged cover. If not, then write down the type of needle on a small piece of paper and stick it with transparent tape on the body.
In any household overlock, the needle is installed with a long groove towards itself, or a sawn off part of the flask away from itself.
Be sure to install the needle all the way, and if you have two needles, they are often offset (one higher than the other).

Overlock sewing threads play a vital role in the formation of overlock stitches. If you use threads of different quality or thickness, this will immediately affect the tension and, therefore, the stitch pattern will change. The overlocker is very “sensitive” to thread tension, and the slightest change in one of them can affect all the others.

Try not to use cotton or thick threads. The thinner and more elastic the thread, the easier it passes in the overedging fabric, needles, loopers and the stitch is better.
Threads on conical bobbins (35) are considered the most optimal for high-quality overlock work. They are thin, strong and elastic and can be easily removed from the conical reel.

It is ideal to use threads of the same brand, changing only the color. But in practice this rarely happens, so when replacing threads with a different type or thickness, their degree of tightening may change. In the event that the stitch turns out to be very ugly and not “correct”, we recommend loosening all the tensioners and, at the slowest speed, gradually increase the tension of each thread, periodically checking which thread and how much you need to tighten.

In “hard” cases, when adjusting the overlock stitch, it is better to use threads of different colors in order to clearly see the tension of each of them, and after adjusting, replace them.

The fabric does not move – The presser foot pressure is too weak.
If the fabric is too thin, the presser foot pressure must be reduced, otherwise the fabric will gather. Increase the presser foot pressure when overcasting thick fabrics. In general, the presser foot pressure should not be changed unless clearly necessary.

Thread break – The threads are not threaded correctly.
Be careful when threading, especially looper threads. In some models of overlockers, threading into the loopers is a rather complicated procedure, and specially curved tweezers are indispensable. Be sure to insert the thread into all the points of its attachment indicated in the diagram. It is enough to skip one fastening and the line will be uneven.

The thread is tangled. Check the spool, maybe the thread has come off the spool and caught on the body part. Check the thread guides and the entire thread path.

Too much thread tension is one of the reasons for its breakage. Thread breakage, skips occur when using a different type of needle (see above).

skip stitches: the needle is bent or dull; the needle is installed incorrectly; a needle is used that is not recommended for use by the manufacturer; the thread is not threaded correctly or one of the thread fasteners is missing; The presser foot pressure is too weak.

Stitches are uneven – The thread tension is incorrectly adjusted.

The fabric is wrinkled – too much presser foot pressure on the fabric; the thread is not threaded correctly or tangled; thread tension is too high. When sewing thin and light fabrics, the thread tension in the overlock stitch should be loosened.

After prolonged operation of the overlocker, the looper compartment and other accessible places should be cleaned of scraps, lint and other contaminants (oil stains). Cleaning is preferably done with a stiff hair brush (for glue).
By the way, excess oil in the area of ​​\u200b\u200bthe needle can ruin the processed fabric. Try to carefully lubricate the nodes in contact with the fabric.

Overlockers should be lubricated at least once every six months, and with intensive use once a month. Instead of an oil can for lubrication, it is convenient to use a medical syringe. With a long needle, you can always crawl into hard-to-reach places, and less oil is consumed.

The instructions provide a lubrication scheme, but you can follow a simple rule - lubricate any accessible places where there is friction of metal parts, even if they are not indicated by the factory in the instructions.

In order to “thoroughly” lubricate all the components of the overlock, it is sometimes necessary to remove the protective covers of the case, but if they are difficult to remove, you can get by with factory marks for lubrication.

Overlock lubrication should be given more attention than a sewing machine, since the overlock works at higher speeds and the lack of lubrication in some nodes leads to overheating and even jamming.

What is the difference between a carpet and an overlock
An overlock is practically no different from a coverlock. It can also do overlock stitching. But thanks to the special design, in addition to the overcasting seam, the carpet lock can also perform a flat seam and even a seam. Since the overlock is much more complicated than the overlock, it can only be repaired at a specialized service center.

Which overlocker to buy
If you do not often use the overlocker, you do not need to purchase an overlocker of an expensive model. Any overlock for 7-8 thousand rubles will perfectly overcast various fabrics, and most importantly, in the event of a breakdown, repair of the overlock will be cheaper.

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We sew knitwear without gaps and looping
Many who have tried to sew knitwear on a conventional sewing machine have noticed that the machine often refuses to make a beautiful and even stitch.Gaps form in the knitted line, the lower thread winds, and sometimes breaks. Why is this happening and how can I fix it?

Overlock 51 class
Overlock 51 class is perhaps the most common brand of industrial sewing machine used in everyday life, in small studios. Although morally this technique has long been outdated and many modern fabrics are simply impossible to process on it with high quality, nevertheless, its use is sometimes justified, especially for processing coarse and thick fabrics.

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Overlock class 51 is perhaps the most common industrial sewing machine used in everyday life, in small studios. Although morally this technique has long been outdated and many modern fabrics are simply impossible to process on it with high quality, nevertheless, its use is sometimes justified, especially for processing coarse and thick fabrics.

One of the advantages of a class 51 overlock is an affordable price. For 3-4 thousand rubles, you can buy a completely “decent” used overlocker. One more thing - the overlocker can overcast fabrics with any thread, including cotton, still of the Soviet type.

Sometimes it is necessary to perform a small repair, setting up an overlock. All instructions for it are lost, there is practically no literature available, and the services of a master are sometimes more expensive than the overlock itself. For this case, we offer you a small recommendation.

Technical characteristics of the overlock 51, 51A class.
Overlock 51 class and 51-A class are used for overcasting the cuts of knitted, dress, linen products with a two- or three-thread chain overcasting seam.
Stitch length from 3 to 6 mm; thickness of materials in a compressed state under the foot up to 2.5 mm; brand and type of needle - 0029 No. 60-70.
The overlock has a needle mechanism and two loopers. It is possible to replace the right looper with a spreader, then the overlock will use only two threads.
The 51-A class overlock is a modification of the class 51 machine and differs from it only in that it uses a two-part differential mechanism for moving tissues. The horizontal movement of the front rail is greater than that of the back rail, due to which the fabric is stretched during overcasting. To put it simply, such an overlock will qualitatively overcast knitted fabrics. Overlock seams will be elastic and stretchable. Pay attention to this if you need to buy a class 51 overlocker.

This industrial sewing machine has centralized wick lubrication of the mechanisms located under the machine platform. For this purpose, a crankcase is cast from below under the main shaft in the housing, which is periodically filled with oil. Lubrication of mechanisms located above the platform of the machine is carried out using an oiler.

It is recommended to lubricate overlock class 51 at least once a month with intensive use. It is necessary to lubricate all rubbing metal components, preferably during lubrication, constantly turning the shaft. It is very convenient to lubricate sewing machines and overlock with a medical syringe.
The overlock has adjustable thread tension, presser foot pressure on the material, stitch length and width.

Proper threading is the main condition for the normal operation of the overlocker. To form a three-thread overcasting stitch, thread the needle thread in the following order:
The thread from the spool or bobbin on the spool stand is first passed through the two rear holes in the thread guide plate.
On itself under the washers of the tension regulator on the same plate.
Through the eyelet of the rear horn of the thread guide plate towards you.
On the left side of the thread puller in the eye (L) of the second horn.
To the left into the hole (P) of the thread guide on the needle bar.
Down into the eye of the needle (I) straight away from you, leaving the end of the thread about 5 cm long under the foot to start sewing.

Threading the right overlock looper is clearly shown in the photo and diagram. We will only comment on some points.
E - note that the thread is threaded from the bottom up.
K - the thread must necessarily pass through this knot, it cannot be skipped.
W - note that at first the thread is wound into the W knot, and then into the K knot, and then it goes into the looper.

Threading the left looper is more difficult because access to the looper and thread guide (E) is limited. Use long tweezers and, if possible, do not pull out the old threads from the overlock, but pull them along with the new threads. It is advisable to stretch one thread at a time.
A - the thread comes out of the sleeve of the body.
D - this thread holder has a slot, and the threads can be “snapped”, it is not necessary to bring it into the hole. B - pay attention to how both threads pass in the loopers. The threads of both loopers must exit from the reverse side of the looper.
To form a double-thread overcasting stitch, the right looper is replaced by a spreader, which is not threaded.

Trimming the edges of the sewn fabrics is carried out with two knives: the upper movable knife 4 mounted on the swinging lever of the knife 7, and the lower one 11, which is fixed in the block 12 on the machine body.
The position of the upper knife 4 is set depending on the width of the overcast.
The upper knife is fixed in the holder 5, which can be rearranged in the ears of the lever 7. To move the knife, it is necessary to unscrew the screw 6 of the clamp 10 on the holder 9 with a screwdriver and move the holder to one side or the other, depending on the width of the overcasting.

To ensure normal trimming of the material, the upper knife 4 with its plane should fit snugly, without a noticeable gap, against the plane of the lower knife 11.
After the upper knife 4 is set in accordance with the required width of the overcasting, the lower knife 11 is brought to it, this movement of the block 12 is carried out by means of the lower screw 14 with round knurling. The front screw 13 on the housing, which secures the block, is first released with a screwdriver.
Both the lower and upper knife can also be adjusted in the vertical direction after releasing the fixing screws: 8 for the upper and 1 for the lower knife.
The lower knife is installed in the block so that its cutting edge is at the level of the throat plate. The upper knife is set so that its cutting edge overlaps the cutting edge of the lower knife by approximately 1mm.
When changing the width of the overcasting, it is necessary to adjust the position of the plate 2 on the presser foot, releasing the pre-fixing screw 3.

A grade 51 overlocker adjusted and tuned by a master seldom requires repair. His knots are strong enough and do not arbitrarily go astray. The reason for the poor performance of the overlocker is usually due to the inept use of this industrial machine.

1. First, keep your overlocker perfectly clean, especially where the looper thread passes. Tow and dust prevent the thread from sliding evenly and cause “winding” and sometimes breakage of the thread.

2. You need to change the needle in the overlock not when it bends or breaks, but periodically, since the condition of the needle directly affects the quality of the overlock stitch.
For thick fabrics and reinforced threads, you need to put a thicker needle, No. 100 - 120.
Needles for 51 overlock have a non-standard size. They are noticeably shorter than other industrial needles and have a thickened flask.Using a different type of needle will cause gaps, knocking during operation, thread breakage and needle breakage. By the way, knocking at work is a bad sign. This means that you are overcasting too thick a section of the product and the right looper “beats” the nose into the overlock foot, or touches it. Do not overcast too thick sections of jeans, drape fabrics. This may damage the looper.

3. The most common cause of poor overlock performance is incorrect thread tension or the use of threads of different twists and thicknesses. A class 51 overlocker is very “undemanding”, but still try to use threads of the same twist and thickness, threads from large conical bobbins are best. To adjust the tension of the threads, you must first loosen everything, and then “tighten each of them. It is very convenient to use threads of different colors for this adjustment.

4. Incorrect threading, especially in loopers, also leads to malfunctions in the overlock.

5. Work on the overlock class 51 is carried out in the same way as on conventional sewing machines. Usually, after the end of the operation, the threads are not cut, but new parts are placed under the foot and the overcasting continues. This reduces the consumption of threads and eliminates the possibility of accidentally pulling the threads out of the eye of the needle or loopers, which causes a loss of time for re-threading the machine.
The direction of the fabrics when sewing on a machine with a knife must be precisely defined, otherwise the edge of the parts may not be cut evenly.

We sew knitwear without gaps and looping
Many who have tried to sew knitwear on a conventional sewing machine have noticed that the machine often refuses to make a beautiful and even stitch. Gaps form in the knitted line, the lower thread winds, and sometimes breaks. Why is this happening and how can I fix it?

What is the difference between overlock and overlock
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Overlock Setting Tips
An overlocker, even a household one, is much more complicated than sewing machines and it is almost impossible to set it up, moreover, it is almost impossible to repair an overlocker without special knowledge and skills. However, it is not always necessary to repair overlocks or adjust them, sometimes it is enough just to adjust the thread tension and it will again overcast the fabric with high quality.

Do-it-yourself sewing machine repair
A sewing machine needs repair more often than an overlocker. As a rule, this is due to a violation of the rules for operating the sewing machine, namely, sewing thick and coarse fabrics that are not provided for in the instructions, using needles and threads that are not intended for this model of the sewing machine.

Sewing machine Seagull
The Chaika sewing machine, as well as the class 51 overlock, are still the most popular models of home sewing machines. Sometimes this is justified, since both of these machines are quite reliable and breakage of metal components practically does not happen to them.

Which overlocker to buy
A modern household overlock is not so expensive, and compared to a class 51 overlock, its capabilities are many times higher. Almost all overlocks of modern models use 4 threads, but can perform 3 and 2 thread stitches. And the presence of a differential rail allows you to qualitatively overcast knitted fabrics.

Inexpensive sewing machine: “Pros and cons”
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How to replace the overlock belt with your own hands
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