The sewing machine doesn't work. How to sew knitwear on a household sewing machine. The sewing machine does not sew: what to do
Any sewing machine sometimes skips stitches in a sewing line. Why do skip stitches occur? In this article, you will learn the main common causes of skipped stitches and how to fix them.
To eliminate skipped stitches in a line you need to contact a repairman sewing machines, but most often, the cause can be eliminated with your own hands.
1. The main reason for the appearance of gaps in a line
Lockstitch sewing stitches are formed as a result of the interaction of the shuttle device and the needle. The nose of the shuttle approaches the needle, removes the loop, draws the top thread around itself and a stitch is formed.
The sewing machine stitch will not have gaps if the settings for the interaction of the hook tip and the needle are followed. Let's look at under what conditions and parameters of interaction of these two parts the occurrence of skipped stitches on a sewing machine is eliminated.
The gap between the needle blade and the nose of the shuttle should not be more than 0.3 mm, or better yet, less. Sometimes this gap is more than a millimeter. In this case, the spout passes next to the loop without catching it. A gap is created in the stitch. It should be noted that this gap is one of the main parameters, but not the only one. Other factors also influence the formation of the needle loop and its reliable grip by the nose of the shuttle: the tension of the upper and lower threads; quality of fabrics, threads; condition and type of needle, etc.
However, the gap between the nose of the shuttle and the needle is the main parameter that affects the occurrence of skipped stitches. And if he more than normal, then it needs to be adjusted.
If the sewing machine skips stitches, and you have already checked the thread tension, the condition of the needle and followed other recommendations, then there is only one thing left to do - adjust this knot. It is very convenient to use a magnifying glass for such adjustments. And before setting up this unit, inspect it with a magnifying glass and make sure that all parameters are normal. If this is the case, then perhaps the reason for the omissions lies in another adjustment, which is discussed in other articles on the site.
2. Parameters for setting the gaps between the needle and the nose of the shuttle
When you are convinced that the parameters of interaction between the needle and the nose of the shuttle are violated, then none of the methods given below will be able to eliminate skipped stitches in the line. Try to independently set the interaction of the shuttle nose and the needle as follows.
If your sewing machine performs a zigzag stitch, then first set the stitch type switch to straight stitch.
Remove the needle plate, presser foot, and lower the needle to its lowest position.
At the moment the needle is raised 1.8 - 2.0 mm from the lowest position, the tip of the looper should pass above the eye of the needle, approximately 1.1 - 2.0 mm, with a gap between the needle blade and the tip of the hook 0.15 - 0 .25 mm. Theoretically, the smaller the gap between the needle blade and the nose, the better. But keep in mind that “overdoing it” can lead to needle breakage and dulling of the shuttle nose.
When adjusting this parameter for sewing thick fabrics, it is better to set the nose of the shuttle above the eye with the maximum parameter, up to 2.0 mm. For thin fabrics it can be reduced, but not less than 1.1 mm. Therefore, set the average value to 1.5 mm. If gaps appear, try changing it.
Do not pull the fabric when sewing by hand. Do not try to sew on a household sewing machine too thick fabrics, leather. Do not use needles that are too thin when sewing thick fabrics, otherwise the sewing machine's needles will not break.
A skipped sewing line on a sewing machine can occur for many reasons. One of them is a low-quality bobbin with edges broken by a needle, broken or bent spool walls. Change bobbins more often. Use plastic bobbins, they rotate easier in the bobbin case.
Sewing machine malfunctions can be detected by external signs. For example, skipped stitches appeared or the upper thread began to loop at the bottom, or the sewing machine began to “knock” while working. Suddenly the fabric began to move poorly or the needle often broke, etc. It is much more difficult to determine the cause of the malfunctions that appear and even more difficult to eliminate them, to repair the sewing machine yourself.
In this video you will learn the reason for the expensive repair of a sewing machine caused by a broken toothed drive belt. You will also learn recommendations on how to avoid this sewing machine breakdown.
To make it easier for you to find a breakdown, we offer a brief overview of the main faults and the reasons for their occurrence, as well as a selection of site articles devoted to these issues. But, before you figure out why a sewing machine or overlocker does not sew or sews poorly, you need to make sure that this model of sewing machine is operated in accordance with its technical characteristics, including, exclude the use of materials, fabrics, threads, needles not specified in the passport or manufacturer’s instructions. Let’s also agree that the threading is done correctly and other basic requirements are met, for example, the seamstress does not pull the fabric towards herself with her hand, etc.
1. Sewing machine malfunctions can be grouped into three groups
All emerging malfunctions and malfunctions in the operation of sewing machines can be divided into three main groups: violations of stitch formation; poor quality stitching; malfunctions in the operation of components and mechanisms.
Disturbances in the stitch formation process: skip stitches; stitch length instability; break top thread; broken bottom thread, etc.
Poor quality stitching: stitch landing; tightening the material in the line; "oblique" line; poor-quality trimming of fabric edges (overlock); poor-quality tightening of threads into a stitch (looping), etc.
Malfunction of machine devices and mechanisms: "heavy" movement of the machine; increased noise during operation; "jamming"; damage to the needle and other parts.
According to these three groups, we will consider possible malfunctions, from the point of view of the reasons for their occurrence, and, accordingly, ways to eliminate them. You can read the entire article, this information will not be superfluous for you. Or you can immediately find the group of reasons you need with detailed recommendations. At the end of each section there is a list of articles, to one degree or another, devoted to these malfunctions. It is important to understand that finding the causes of sewing machine malfunctions is intuitive. Various kinds recommendations can only be used as a guide to the direction of the search. An experienced master does not use a “smart” book, he relies only on practice.
2. Reasons for violations of stitch formation in a line
Skipped stitches. The most common reason for stitch skipping in any sewing machine is the lack of a “confident” grip of the needle thread loop by the nose of the hook or loopers. Adjusting this parameter of a sewing machine always requires experience, especially with overlockers. The formation of a loop near the eye of the needle occurs when the needle is raised from the lower position by approximately 1.8 - 2.3 mm. The nose of the shuttle or looper should at this moment pass just above the eye of the needle and almost close to the needle blade. Since it is not always possible to perform high-quality settings for these parameters yourself, we only recommend checking them. This will allow you to determine that the cause of the skipped stitches may be due to another problem.
The occurrence of a skip may be influenced by the compensation spring.
Blunt nose of the shuttle.
When the thread number does not match the needle eye size (thread is too thick).
Large (broken) needle plate hole.
For thin fabric, a needle that is too thick is used.
The needle in the needle bar is loose.
The needle is not installed correctly.
The appearance of excessive play in the components and mechanisms of the machine.
Defective needle.
Broken upper and lower thread. The most common causes of thread breakage can be: thread abrasion; cutting thread with sharp edges of parts; thread rupture due to pinching, overlapping, etc. To detect places where the thread breaks, you need to inspect the entire route of the thread (you can use a magnifying glass). Probable causes of thread abrasion may be: the roughness of the thread guides and surfaces in contact with the thread in the area where it breaks; too much thread tension; decrease in the strength of the thread due to its unwinding. See also:
Reasons for skipping stitches on a sewing machine
Sewing stitch - thread breakage
Industrial sewing machine 1022 class
Sewing machine problems
Do-it-yourself repair and adjustment of overlockers
How does a sewing shuttle work?
Tight stitch. The stitching is pulled together most often due to excessive tension on the top thread and too little pressure of the presser foot on the fabric. First adjust the tension of the lower thread, then set the correct tension of the upper thread. The interweaving of the top and bottom threads of the stitch should be inside the fabric. Adjust the presser foot pressure so that when the presser foot is lowered and the teeth of the feed are raised (the needle is above the presser foot), the fabric can only be pulled out with noticeable force. A rough surface of the presser foot (worn out) can also cause the fabric to pull together in the stitching. The stitching will tighten if the worn teeth of the rack do not advance the fabric well. Therefore, it is not recommended to set the sewing machine in motion with the presser foot down and without fabric.
Fabric tightening. May occur when the fabric motor and needle malfunction. It is difficult to adjust such a breakdown on your own, but you can check it. The teeth of the rack should completely lower ("hide") at the moment when the needle almost approaches the needle plate (1.5 -2.0 mm).
Poor quality cutting of fabric with overlocker. Dull overlock knives do not cut fabric well, which leads to gaps and permanent stitch tightening. A characteristic dull knock when the overlocker is operating indicates that the knives and needle have become dull.
Poor quality stitching. The so-called “loop”, as well as oblique stitching, is formed due to excess top thread. As a rule, the reason for this is the appearance of roughness along the path of the upper thread or a violation of the shuttle stroke settings (Chaika sewing machine). See also:
Why does the line loop?
Sewing machine feet
Sewing threads, which ones are better?
How to thread a sewing machine
Seagull sewing machine
Setting up a sewing machine. Reika - fabric advancement
Overlock 51 class
4. Malfunction of the components and mechanisms of the sewing machine
Heavy running of the sewing machine. Most often this is caused by a lack of lubrication, clogging of the shuttle mechanism with tow, thread trimmings. Often, heavy running of the machine may occur after replacing the electric drive belt. A belt that is too tight makes it difficult for the sewing machine to rotate easily and causes parts to make noise during operation. Excessive tightening of fasteners and connections of machine parts also makes it difficult for them to rotate.
The sewing machine jams. Sewing machine jamming can occur after long-term storage of the machine. If the machine has not been used for a long time, it is recommended to lubricate it first, and then operate the sewing machine without thread for several minutes. Using the wrong oil will also cause the sewing machine mechanisms to jam. Some types of oils can dry out over time, especially when high temperature air. They turn from oil into glue, which most often becomes noticeable after a long period of “downtime”. Rarely, parts can break down, leading to malfunction of the machine.
Needle breakage. Needle breakage usually occurs due to inept seamstress work. The fabric should not be pulled towards you by hand. Correctly adjust the presser foot pressure on the fabric and the lifting height of the dog teeth, and you will no longer need to “help” the machine with your hand. When sewing coarse fabrics, a needle that is too thin is used. A needle is used that is not intended for this model of sewing machine. The needle is not inserted into the needle bar all the way. The needle is not centered on the plate's needle hole. See also:
Reasons for a broken needle on a sewing machine
Sewing machine lubrication
Electric sewing machine drive
Flywheel - Singer
How does a sewing pedal work?
How to replace an electric drive
This article contains all the typical and simple faults and repair methods for a sewing machine.
How does a modern household electric sewing machine work? Basic malfunctions of components and mechanisms.
This article contains expert advice on how to independently disassemble a modern household sewing machine from Brother, Janome, etc.
Such a “trifle” as winding thread on a bobbin often creates a lot of inconvenience when sewing. For some reason, it is not always possible to do this quickly and “without problems.” Let's figure out why it is sometimes difficult to wind thread onto a bobbin and what needs to be done to fix minor damage to the winder.
It's rare, but sometimes you can find foot-operated machines. The best solution, instead of repairing the foot drive, install an electric drive on the machine. This is not difficult to do and anyone with a screwdriver can install it with their own hands. But, if you still need recommendations on how to repair or adjust the foot drive, this article is at your service.
The main malfunctions and malfunctions of these sewing machines, as a rule, are not related to its adjustment. Sometimes it is enough to install the needle correctly, replace low-quality threads, select the correct tension of the lower and upper threads, and the machine will work perfectly again.
If the foot drive is, one might say, a complete antique, then the manual drive can be used, especially for beginners learning to sew. Read this article to learn how to repair this device yourself.
Sewing machine faults and problems It will be easier to fix if you understand how the sewing machine works and which part is used for what. Study carefully the structure of your machine according to the instructions or using our article.
Why did a modern household sewing machine suddenly start skipping stitches? The sewing machine repairman explains.
Poor stitching means weak or too tight stitching with uneven or askew stitches, looping at the top or bottom, unsightly or dirty.
Reasons for bad stitching:
incorrect thread tension;
unequal thickness of the upper and lower threads;
weak pressure of the foot on the fabric;
sewing with a curved or blunt needle;
poor quality slats;
poor rack performance;
inconsistency in the operation of the fabric engine and the shuttle;
sewing on a machine that has not been cleaned for a long time or has just been oiled and not wiped.
A weak stitch is considered to be one whose threads are visible between the stitched panels.
If the stitching turns out to be weak, you need to increase the tension of both threads (top and bottom) and adjust it to normal, and first you need to slightly increase the tension of the bottom thread, and then, while sewing, gradually increase the tension of the top thread until it is the same for both threads.
A tight stitch is considered to be one in which thin soft fabric is pulled together and gathered, but on thick, dense fabric the stitching is weak, i.e. when the fabric is slightly stretched along the stitch, the threads break.
Rice. 2. PMZ (Podolsk sewing machine)
If the stitching turns out to be tight, you must first loosen the bottom thread a little, and then, while sewing, adjust the tension of the top thread along it. If this weakening is not enough, you need to loosen the lower thread a little more, and then the upper one, adjusting until the thread tension becomes normal (not very tight and not weak) and the same for both threads. If the machine loops at the top or bottom of the fabric being sewn, it means that the thread tension is not equal. To fix this problem, you need to determine which thread is looping - the top or bottom.
Loops 5 (see Fig. 28, a) on the underside of the fabric are made by the upper thread if it is stretched much looser than the lower one. In this case, you need to increase the tension of the upper thread and stitch. If loops 5 at the bottom have disappeared, and loops 6 at the top have appeared (Fig. 28, c), it means that the top thread is now tighter than the bottom thread. Adjustment of thread tension should be carried out until the loops disappear on both sides of the fabrics being sewn.
If the loops do not disappear, then the cause of the looping may be inconsistency in the operation of the fabric motor with the shuttle, which can be eliminated in the workshop.
If bad stitching occurs due to the “rolling” of the rack, you need to tighten the screws securing the rack to the rack fork more firmly (see Fig. 46, a).
If the rocking of the rack occurs due to the rocking of the rack fork due to the loosening of the screws that connect the parts of the fabric motor mechanism, you need to contact a workshop. If oblique stitches are obtained due to the difference in the thickness of the upper and lower threads, you need to thread the same threads into the machine.
Oblique stitches can be made by a crooked needle, which should be replaced.
Oblique stitches can also be obtained by swinging the slats to the right - left, along the platform, when, due to the displacement of the slats, the fabric also moves. In this case, strengthen the rack screws.
If the stitching is obtained with stitches that are uneven in length, it is necessary to check the pressure of the presser foot on the fabric, the fastening of the foot and the condition of its sole. How to change the pressure of the presser foot on the fabric and tighten the fastening screw was discussed above. If there are uneven spots on the sole of the foot, the foot needs to be changed.
Rice. 28. Looping threads with a stitching stitch: I - top view of the stitch; b - looping of the upper thread; c - looping the lower thread
Uneven stitching, with frequent and sparse stitches, can be obtained by rocking the staff back and forth (from the worker to the worker). To avoid this, tighten the screws securing the rail.
If you need to tighten the screws connecting other parts of the fabric motor mechanism, then you need to turn to the help of a workshop.
The reason for the uneven length of the stitches may be the wear of the rack teeth when some of them have already stepped. The solution is to change the rack.
When sewing products from very thin, but not transparent fabrics, even thin threads Almost always (if the fabric is not soft enough) the interlacing of the upper and lower threads is noticeable on the front side.
In order for this weave to be visible only from the wrong side, you should slightly loosen the tension of the upper thread.
An ugly stitch is obtained when thin fabric is sewn with thick threads, but if, on the contrary, thick fabric is sewn with very thin threads, then the stitching will be fragile.
Dirty stitching results from a machine that has not been cleaned for a long time. In this case, in a PMZ machine (Podolsk sewing machine), you need to disassemble the shuttle set and wipe each of its parts.
Most often, dirty stitching results from the fact that they sew immediately after lubricating, without wiping the machine, and not on a piece of scrap, but directly on the fabric for the product.
In addition to the problems that fall into the main six groups, there are others, for example, when the machine knocks very loudly or has a hard ride. The machine does not turn on after winding the bobbin because the flywheel 1 (see Fig. 2) is not connected to the main shaft 2 or is not turned off before winding the bobbin. In sewing machines that make zigzag stitches, there are problems with the control levers, and in those that have a copying device (automation), there are problems with stars or automatic levers.
The machine knocks loudly if it has not been cleaned, lubricated for a long time, or if it has been lubricated with stale, thickened oil.
The machine must be promptly and thoroughly cleaned, lubricated with fresh machine oil, and if it has not been cleaned for a long time, even washed with kerosene.
Loud knocking of the machine and even its stopping can occur due to the thread getting stuck in the shuttle set.
The reasons for thread getting into the shuttle set are: turning the handwheel away from you when the thread is threaded into the needle, or rotation of the handwheel when the presser foot is raised and the thread is threaded into the needle.
Not in all cases and not in all machines, when thread gets into the shuttle set, it is necessary to disassemble it in order to remove the thread stuck in it, but to do this you always need to remove the bobbin case from the machine. If the needle is in the up position, the bobbin case can be removed immediately. If it is lowered, that is, it is in the shuttle set, you must first remove the needle from the machine.
When the bobbin case is removed from the machine and the thread is removed from the needle, you need to try to forcefully turn the flywheel half a turn away from you, and then the same amount towards yourself. If this cannot be done, you need to put oil on the shuttle track and then try to slightly turn the flywheel away from you. If the wheel does not turn or the loud knock of the machine cannot be eliminated, then in the PMZ machine (Podolsk sewing machine) you can disassemble the shuttle set, remove the stuck thread and, after wiping all the parts, reassemble the set.
The thread does not get stuck in the shuttle set of the Tula machine, and it is accessible for cleaning without disassembling.
Rice. 46. Working with a darning foot: a - darning and embroidery foot, installing an embroidery plate; 6, c, d, e and f - sequence of operations when installing the embroidery plate on the needle plate; g and h - installation of a darning foot on the machine (with an external spring); and and k - darning feet (with an internal spring)
In the car. "Veritas" if the thread gets stuck in the shuttle set, it does not need to be removed or disassembled. You just need to remove the needle and remove the bobbin case from the machine, try to forcefully turn the flywheel one third of a turn away from you and make several rocking movements. If, as a result of this, the thread stuck in the shuttle set does not fray or fall out of it, then you can loosen the screws of only one removable plate 5 (Fig. 83, a) of the shuttle set, which goes around it almost halfway and has the shape of a narrow strip. One end 6 (Fig. 83, b, c) is sharp and faces the nose 7 of the shuttle, the other end 8 (Fig. 83, a, d) is smooth and closely adjacent to the permanent plate 9. The thread can only get stuck under the plate 5, which you can remove yourself. It is attached to the kit with three screws 10, 11 and 12 arranged one after the other (Fig. 83, a). If, after loosening these screws, the thread cannot be pulled out from under plate 5 (it breaks), then screws 10, 11 and 12 are completely unscrewed, plate 5 is removed and the stuck thread is taken out.
Screws 13 (Fig. 83, d), 14, 15 and 16 of the permanent plate 24 do not need to be loosened or unscrewed, so their caps are ground flush with the surface of the permanent plate.
To clean the shuttle set, do not unscrew screws 17 (Fig. 83, a), 18 and 19 (Fig. 83, d), securing the shuttle set to the shuttle shaft. If, due to poor shuttle performance, it is necessary to loosen or remove these screws, this can only be done in a workshop, because a thorough knowledge of the rotary hook machine and installation experience is required to accurately determine the distance from the hook nose to the needle and the approach time her. The slightest inaccuracy in installing the shuttle set in the machine can lead not only to skipped stitches and broken needles, but also to the nose of the shuttle becoming dull on the needle and even to its breakage, then you will need to replace the permanent plate or the entire shuttle set.
Loud knocking, skipping stitches, poor stitching and needle breakage can occur when screw 20 (Fig. 83, d) of pin 21 is loosened. It is necessary to check the fastening force of screw 20 in groove 23 of the fastening and, if it is loose, tighten it. To do this, you need to install the finger 21 so that its end 22 does not touch any of the walls of the groove 23 through which the thread passes (there should be a small distance between them). Then, while the machine is running, the thread will pass freely through the groove.
Rice. 83. Shuttle kit of the Veritas machine: a - the position of the removable plate, providing access to all three of its screws; b - the same, to two screws; in - the same, to one; d - position of the permanent plate attached with four screws
Heavy running of the machine is observed when the drive belt tension is very high in foot-driven machines. In this case, you need to buy a longer drive belt and put it more loosely on the flywheel of the machine and the drive wheel of the machine.
Another reason for the heavy running of a manually driven Tula machine may be working on it without turning off the electric motor.
In addition, machines that are not lubricated and have not been cleaned for a long time have a heavy, “stiff” movement.
If by turning the friction screw 5 towards you (Fig. 84, a, b), it is not possible to turn off the machine, that is, to disconnect the flywheel from the main shaft, and the needle continues to work while winding the thread onto the bobbin, then the reasons for this may be: dryness of bushing 6 (Fig. 84, b), incorrect position friction washer 7, shown in Fig. 84, b, c, d, or incorrect rotation of friction screw 5 (Fig. 84, b).
If the reason the machine does not turn off is a dry bushing, you need to let oil into hole 8 on the flywheel.
Rice. 84. Removing and installing the friction washer: a - removing the friction screw; b - removing the friction washer (the washer and screw are shown separately); c and d - friction washer in various working positions
If the needle continues to work after lubrication, it is necessary to check the condition of screws 5 and 9.
If the limit screw 9 and the friction screw 5 are screwed correctly, the reason for the non-disconnection of the flywheel from the main shaft is the incorrect position of the friction washer 7 (Fig. 84, b, c, d).
To check the position of this washer, you need to unscrew the limit screw 9 (Fig. 84, a, b) of the friction screw 5 and remove the friction washer 7 (Fig. 84, b, c, d), which has three horns 10 (Fig. 84, c, d), 11, 12 and two protrusions 13 and 14. In the bushing 6 (Fig. 84, b) of the flywheel, into which the friction washer is inserted, there are two recesses - grooves 15 and 16. Protrusions 13 and 14 (Fig. 84, c, d) the washers must, firstly, fit into the recess of the sleeve and, secondly, with their bent ends facing outward, since they serve as a stop when rotating the friction screw to turn off or turn on the needle mechanism. Insert this friction washer into place before
quite difficult, it moves out of the installation site when screwing in the friction screw.
If you hold the machine with the flywheel up (head down), it will be easy to put the friction washer 7 and screw in the friction screw 5, and then the limit screw 9 (Fig. 84, b). If, when winding the thread onto the bobbin, the needle continues to work, you need to take out the friction washer 7 again (Fig. 84, c), but do not turn it over, but only turn it 180° in a circle (Fig. 84, d) so that only the horns 10 11, 12 swapped places, tighten the friction screw 5 (Fig. 84, a), screw the limit screw 9 into it.
When turning the machine on or off, the friction screw 5 can be turned no more than 73 turns, i.e. from one protrusion 13 (Fig. 84, c) of the washer to another 14 or, conversely, from the horn 11 to the protrusion 13. If you translate through them, the inner end 17 (Fig. 84, b) of the limit screw 9, then the washer 7 can turn, but will not disconnect the flywheel from the main shaft or turn on the machine, i.e., will not connect the flywheel to the main shaft, then it will rotate at the so-called idle speed.
In the Veritas machine, the separation and connection of the flywheel to the main shaft occurs in exactly the same way as in the PMZ machine (Podolsk sewing machine). In the Tula machine, when winding a bobbin using an electric motor, the flywheel does not rotate, because it is mechanically turned off along with the main shaft. The thread is wound onto the bobbin using a special device on the electric motor shaft.
Problems associated with the operation of the electric motor can be eliminated by electricians in consumer service workshops.
