Home Article Why the sewing machine knocks when sewing

Why the sewing machine knocks when sewing

Poor sewing stitching

Tightened stitching. Creasing of the stitch is most often caused by too much upper thread tension and too little foot pressure on the fabric. Adjust the tension of the lower thread first, then set the correct tension of the upper thread. The intertwining of the upper and lower threads of the stitch must be within the fabric. Adjust the presser foot pressure so that with the foot lowered and the feed dogs raised (needle above the foot) the fabric can only be pulled out with a noticeable effort. Rough (worn out) presser foot can also cause pulling in the stitching. The stitching will be tight if the raker teeth are worn and do not move the fabric well. Therefore, it is not recommended to move the sewing machine with the presser foot down and no fabric on the foot.

Tightening of the fabric. Can occur when the fabric and needle motor malfunctions. It is difficult to adjust this defect by yourself, but it is possible to check it. Rack teeth should be completely down (“hide”) at the moment when the needle is almost approached to the needle plate (1,5.2,0 mm).

Poorly trimmed fabric with an overlock. Blunt blades overlock bad cut fabric, which leads to skips, nerazmalnaya tighten the stitch. A loud thud when the overlock works, indicates blunted knives and a needle.

Poor quality stitching. The so-called “looping”, as well as the oblique stitch is due to an excess of the upper thread. As a rule, the cause of this appeared roughness on the path of the upper thread or violations of the settings of shuttle stroke (sewing machine Chaika). See. Also: Why is the stitch looping Sewing machine foot Sewing machine threads, what is the best? How to tuck a thread into a sewing machine Sewing machine Chayka Tuning sewing machine. Rack. Promotion of fabric Overlock 51 class

Pretty thin walls of the cam track of the crankshaft (crank) easily worn with frequent work. Knocking of the take-up roller against the corner. Timely replacement of the cam can prevent serious machine damage. Only an expert can locate the problem and install the part.

Disproportionate tightening of the shafts of these parts greatly affects the running of the machine. Longitudinal play should not be felt by hand, but an excessive increase in play can also cause a knocking noise when stitching. How much to release the taper of the small shaft and how much to set the longitudinal clearance for a sewing machine a certain brand has only the knowledge of an experienced technician.

You should always pay attention to the sounds the sewing machine makes when it is running. They are not only unpleasant to listen to. they may be the first symptoms that tell you that something is wrong with the device. It is important not to ignore even light knocks. Insignificant at first glance, they indicate a more serious, outwardly inconspicuous malfunction, for example:

  • Internal parts get dirty. Dust settles on the gears of the machine, making operation difficult and mixing with the oil. Small debris getting inside can lead to subsequent malfunctions that provoke noises while sewing. That is why the sewing machine needs regular maintenance. it is necessary to carry out its maintenance at regular intervals.
  • Conveyor clogging. While sewing, the fibers from the moving cut remain on the conveyor belt. It does not clog immediately, but the trash gradually accumulates and prevents a smooth movement of the mechanism. Therefore, the part should be cleaned occasionally.
  • Wiping parts. Due to improper machine settings, friction can occur between its mechanisms, which leads to their erasure. As a result, there is a knock and noise, as well as a number of related malfunctions.
  • Warped needle. When the needle is deformed or the needle bar is tilted, it begins to jam in the needle plate. These are interdependent faults. If they are not corrected in time, the needle can break off.
  • Incorrect thread position in the hook. It causes the hook mechanism to prevent the thread from running freely. As a result, it gets stuck, forming numerous knots, or breaks off.
  • Wear of the crank. If this is the case, replace it. is the only way out.
  • High tension on the small shaft and the rocker arm. As a consequence. The machine is unyielding, sewing hard and slowly.
  • Defective bearings. Their fasteners may be loosened, which, if not taken care of, will loosen even more.

Why the sewing machine is very noisy?

Normal operation of the sewing technique and high quality sewing is only possible with the proper adjustment and tuning of all its parts and mechanisms. The appearance of atypical noise, knock, hum during operation is a sign of malfunction. Diagnose and fix the problem, which caused a noisy sewing machine, you will help professionals Private Masters Association Needle. We have been working in this area for a long time and have a lot of experience. Under the belt of all our masters we have performed a lot of successful repairs of sewing machines of different brands. We will restore your sewing machine, even after a serious failure. Call us at 8 (495) 745-20-50.

Knocking in the machine.

Blunted needle from prolonged use or from the impact of the needle on the foot, needle plate, hook. This causes many times more resistance when piercing the fabric, which increases the knocking in almost all joints, wearing out parts, reducing the service life of the machine

Needle like this can be replaced or sharpened. Chapter. 2 “Needle mechanism”).

Needle after impact must be changed. First of all, the noise increases, and most importantly, spoils the fabric that is stitched.

In a narrow channel of the toothed rack of the cloth engine pressed fleece with dirt. Every time the rack is lifted, the needle plate is bumped.

Remove the needle plate and clean the narrow groove in the rack.

Tilt the machine on the hinges, remove the bobbin case, unscrew the screw fixing the plate spring on the hook stroke housing, remove the locking bracket, take out the hook and clean the groove. Reassemble assembly in reverse order. Don’t forget to put the support ring with the bevel (at the ends) facing outward (for 2M cl. PMZ).

Clean and lubricate the hook on a regular basis.

Idler roller bangs against the corner of the groove, formed by severe wear in the cam of the crankshaft. Second cause of knocking may be a breakage of the very thin wall of the groove on one of the cam section (crank).

Main shaft eccentric was sold complete with the main shaft. The work of replacing the eccentric is very time consuming, you must have a knockout for the main shaft.

Pfaff Hobbymatic Sewing Machine: It’s Noisy And I Don’t Know Why

Tighten the small shaft with the rocker arm (the movement of the machine is very sensitive to the tightening of this particular shaft).

Loosen the small-shaft cone enough so that movement is smooth and backlash is not felt by hand.

Loosen the cone bolts, rotate the machine and adjust the stub shaft. No backlash and easy running is the prerequisite.

Set the shaft end-to-end clearance so that it is only slightly felt by hand. large clearance causes a knocking noise in the machine (see: “Pitching”). Ch. 1 “Stiff machine running”).

If there is a large backlash, fluoroplastic spacers are helpful. eliminates noise and maintains ease of movement.

play in the connecting rod bearings of the crankshaft has developed because the fastening screws are worn out or loosened.

Remove the bearing cover and file the surface of the bearing cover (see “Remove the bearing cover and file the surface of the bearing cover”). r. 2. “Crankshaft Mechanism,” n. 2 и 4).

a piece pinches a neighbouring piece, e.g. rocker slide, at higher flywheel speeds pinches the lug on the feeder shaft.

sewing, machine, knocks

This fault is difficult to detect: remove one by one all parts and assemblies from the machine and try to turn the flywheel at high speed. In this example, saw off the eyelet by 1 mm.

The fork horn of the rack lift shaft strikes the platform (presence of shiny dots of different size on the fork and platform). This shaft is upper when the machine is tilted to the rear.

Remove the upper rack lifting shaft. Carefully wipe the fork and the place where it touches the platform with a rag. Saw the contact points to a depth of 0.5 mm.

There is a big gap between the shuttle and the pusher.

Bend the pusher to the side of the shuttle. The gaps should be as follows (for the 2M cl. PMZ): at the entrance of the thread 0.3 mm; at the exit of the thread 1 mm.

The leaf spring on the shuttle pusher is broken.

Install a new leaf spring. It can be made from 0,4 mm thick steel tape. When installing a homemade plate it is important not to allow the heads of the screws to rise above the plate, otherwise the upper thread will catch on them and break off.

Replace with a new one, t.к. holes on the spring are made with projections for screws.

The rack is set incorrectly. When moving downwards, it catches on the needle plate.

Troubleshooting Quick Snip Machine Making A Knocking Noise

Remove the needle plate, loosen the screws securing the rack and install it without tilting.

Tighten the upper and lower shafts of the fabric motor.

Loosen shafts in cones. Backlash should be barely perceptible by hand.

The needle is in its lowermost position and the rocker is turned inward. As a result, the slider in the rocker arm is knocking on the small shaft.

Remove the stub shaft and file off 0.5 mm of the striking contact on the stub shaft with an emery board. When installing the small shaft, note the following: the clearance in the shaft tapers is not felt by hand, but rotation is light; the clearance in the connecting rod bottom bearing is barely felt by hand; when turning flywheel a few turns, there should be no stick-slip.

Screw on the needle bar lever turned out and is rubbing the arm housing.

Remove the front cover, tighten the leash screw until it stops, then unscrew it by 1/3 turn.

Lateral play of the main crankshaft. a frequent occurrence, especially in “Chaika” machines.

Remove the front cover, put the machine on the flywheel and try to move the cam of the crankshaft towards the flywheel. If the play does not disappear, put a foil washer under the flywheel bushing. To remove it, press out the round pin (conical).

It is better to remove the friction bushing, install the spacer, bushing and hammer the cotter pin.

Forked lever of cloth motor knocking on the platform.

Remove the shuttle stroke housing, the shuttle pusher shaft and the bottom feed. Locate where the fork contacts the platform and file them down 0.5mm. Reassemble in reverse order. When reassembling, adjust the distance (it is 2 mm) between the hook nose and the needle when it is at the extreme lower position.

The outlet end of the pusher is caught in the hook stroke housing.

Use a screwdriver to bend the output end of the push rod by 0.5 mm. Adjust the clearance between the hook and pusher. At the input of the thread it should be 0,3 mm, at the output 1 mm (for 2M cl. PMZ).

The handwheel drive lever is caught on the rewinder when winding the threads.

Remove the manual drive and saw off a corner of the hand lever by 1,5-2 mm.

One or more teeth on the hand wheel are broken.

“Thump, Thump, Thump”. Said The Sewing Machine. Machine Tip

Replace manual drive. If you remove one pinion, it is very difficult to find another one.

Adjust the moment of the needle and hook encounter (see “Thread inlet”). Chapter. 3) and firmly tighten needle bar fixing screw.

Adjust stroke and position of needle bar and hook.

Screw securing the thread tensioner is loose. This defect is rare.

Screw the screw securely with a large screwdriver.

Presser foot is set too high. Needle bar bangs on it when sewing thick stitches.

Remove the front cover, remove the screw fixing the presser foot in the bracket and lower the foot so that the needle bar does not touch it when turning the handwheel. When adjusting presser foot level, lift lever must be raised.

Fault in the connection of the foot control.

The foot controller must work quietly (see “No noise from the sewing machine” on page 54). Chapter. 2 “Foot Drive”).


To restore operability, you need to diagnose the fault and determine the best way to fix it. Common breakdowns and repair methods are shown in the table below.

This is not a complete list of faults. By your own hand to determine the problem, trying to repair it is dangerous, there is a high probability of breaking the device, increasing the cost of repair at times.

Sewing machine makes knocking and noise

If you hear an unusual knocking or noise when using the sewing machine, it is always a sign of malfunction. Even if the machine still seems to work normally, but you hear a knock or noise, then the work should immediately stop and conduct a complete inspection of the work of all mechanisms and units. Only this way you can identify a failure.

Sewing machine noises when working? Professional craftsmen “SueRem” quickly identify the cause of the knock and make high-quality repairs sewing machine Brother, Pfaff, Juki, Bernina, Merrylock, Jaguar, Singer, Veritas, Podolsk, Chaika and other manufacturers. Repair your equipment master can make at home or in the studio. You can call our masters by phone 8(495) 213-18-17 from 8:00 till 23:00 on any day of week. We work without weekends and holidays. You can also leave an application on the website.

The technology of the equipment in question is the same for all manufacturers, such as Janome, Juki, Brother or Pfaff. However, there are unique features of design and hardware. Therefore, it is difficult to uniquely identify the cause. The most common ones are:

  • The formation of a gap between the bushings of the shaft.
  • Toothed rack loosened, which causes it to bump the needle plate.
  • Stability of the foot drive is disturbed.
  • The shafts underneath the platform are severely compressed due to improper adjustment.
  • Use of an overly thick needle. In this case, the pivot joints are knocking. The problem is not dangerous if it is quickly corrected. Continued operation threatens serious malfunctions and breakdowns in the thread guides.
  • Debris accumulating on the oil surfaces. When a small part is covered with dust, lint, it compacts and becomes wider/higher in size, which causes it to bump against neighboring products during start-up.
  • Expansion of the gap between the forks and the shuttle.

Naturally, these are not all malfunctions accompanied by the appearance of a characteristic knocking. It is necessary to know exactly how each individual unit works in order to find the problem area and neutralize it.

Experts say that every malfunction is the result of a malfunction of some kind. Most often, the cause of knocking is a failure to follow the recommendations for care, namely, if the surface of the mechanisms accumulates dust and lint from the fabric, in the process of operation has not been performed lubrication.

Lack of oil on the surface of the interacting parts leads to rapid wear, and its first sign is manifested as a knock.

In addition, there are other reasons why the sewing machine knocks. They do not depend on the model, and are inherent in each brand Janome, Singer, Pfaff, Juki, etc.

Let’s dwell on them in more detail and consider methods of elimination.

  • A blunt or bent needle will catch on the edge of the needle plate, creating noise. Replace the needle and make a test stitch. If the knocking has not stopped, the needlewheel may deflect, this malfunction requires repair.
  • Stuck upper or lower thread in the hook cause knocking, this malfunction often occurs during sewing zigzag stitching, as well as if the upper thread is loose and starts to loop when sewing.
  • It may happen that a whole lump of thread is formed in the hook mechanism and the needle gets stuck in it. In this case, do not jerk the thread, to avoid breaking the needle, because it can be in the hook. To fix the situation, you need to take manicure scissors, carefully trim the threads, pull them out in parts.
  • If between the teeth of the fabric conveyor lint is packed, the remnants of threads, they begin to contact the needle plate, creating a sound. For quality cleaning of the rail, you need to remove the plate and remove debris with a brush.
  • It happens that the toothed rack is skewed, for this unscrew the screws that hold it in place and set the plate straight.
  • When using a sewing machine is subjected to vibration, and the screw that holds the needle is loosened. This is also the reason for a knocking sewing machine. Use a special screwdriver to tighten the screw.
  • If the hook in the sewing machine knocks, the leaf spring may be broken. In this case you need to replace the part.
  • A drive belt that is too tight can make a noise. For normal operation, it must sag by one centimeter.
  • If the presser foot is set high, it will bang against the needle bar during operation.

These malfunctions occur in external parts, and every seamstress can diagnose and eliminate the causes on their own.

There are also internal mechanism failures. Only a master can locate them and eliminate the knocking. Specialists recommend not to perform this repair yourself for several reasons

  • Not having experience, it will be difficult to accurately determine the location of the fault, and you can cause even more damage to the equipment;
  • even if the noise occurs, if no spare parts are available, it will not be possible to repair it;
  • Any change of parts requires subsequent adjustment, and this task can only be handled by a master.

In order not to face expensive repairs, at the appearance of the first noises, it is necessary to stop the work and, if knowledge allows, to check the visible assemblies. If the fault is not detected, you need professional intervention.



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