The situation when a sewing machine suddenly begins to shed the bottom thread, forming an endless tangle instead of a neat seam, is familiar to every craftsman. This phenomenon, often referred to as a “beard” or “loop”, can take you by surprise at the most critical moment of working with fabric. Instead of enjoying the process of creating clothes, you are forced to spend precious time unwrapping the seams and finding a fault.
The reasons for this behavior of the mechanism can be completely different: from an elementary error during refueling to a serious displacement of parts in the system. shuttle-knot. Often the problem lies in the banal mismatch of the thread thickness of the chosen needle or in the fact that the upper thread simply did not fall between the tension discs. Understanding the physics of the stitch formation process will help you diagnose a breakdown quickly.
In this article, we will examine in detail all possible scenarios why the sewing machine loops from the bottom, and provide a step-by-step algorithm of actions. You don’t need to be an engineer to set up the technique, just check the key settings carefully. We will consider the tension settings, the condition of the needle, the quality of threads and the features of working with knitwear.
Disturbance of the tension balance of the upper thread
The most common reason for the appearance of hinges from below is too weak tension of the upper thread. The mechanism of the seam works on the principle of interlacing: the upper thread should tighten the lower one in the tissue thickness. If the regulator is at a minimum, the thread goes down freely, forming those very sloppy loops. Adjustment is carried out using a special unit on the body of the machine, usually located above the needle.
However, just spinning the handle of the regulator blindly is not the best strategy. It is necessary to make sure that the thread correctly passed through all the guide hooks before entering the tension mechanism. It often happens that the thread jumps off the lever or gets stuck between the disks, and then even the maximum value on the scale will not give a result. Check the path of the thread from the reel to the needle, making sure it lies in the grooves, not on top of them.
⚠️ Attention: Never adjust the tension of the upper thread while the needle is in the fabric or the foot is lowered without the tissue underneath. This can lead to deformation of the tensioner discs.
It is also important to consider the type of tissue. For a thin chiffon and tight jeans require completely different settings thread-tension. If you have switched to a new material, be sure to make a test stitching on the patch. The optimal seam is considered where the nodule of the connection of threads hides inside the tissue, and is not visible from either above or below.
- 🧵 Check if the filament has fallen between the tension regulator discs.
- 🔢 Increase the value on the regulator (usually by turning clockwise).
- 🧶 Make sure the coil with the threads rotates freely on the holder.
- 👁️ Examine the tension spring for the sticking of the villi.
Needle problems: installation, type and condition
The needle is the heart of the sewing process, and the slightest defect in this part instantly affects the quality of the line. If the needle is installed with a blunt end (bulb) in the wrong direction, the mechanism will not be able to capture the loop of the lower thread in time. In most household cars Janome or Brother the flat side of the bulb should look back or to the right, but it is better to check the instructions for your model.
A dull or bent needle is another frequent culprit in the formation of loops. Passing through the fabric, the deformed tip shifts the fibers of the material and disrupts the trajectory of the thread. This means that the top thread is not pulled at the right time. In addition, using a needle that is too thin for dense tissue makes you exert yourself by pushing the material, which also knocks the rhythm of the mechanism.
There is a misconception that one universal needle is right for everything. In fact, knitting requires needles with a rounded tip (Jerseyand for the jeans, with a strong edge (Jeans). Incorrect choice of the type of needle leads to the passing of stitches and the reset of the thread. Always select the needle number according to the thickness of the threads and the density of the material.
- 📏 Find the right needle number (such as 75 or 90) for your fabric.
- 🔄 Replace the needle if it has been used for more than 8-10 hours.
- 🔍 Make sure the needle is inserted to the point in the needle holder.
- 🧵 Use specialized needles for elastic fabrics.
Refilling errors of the lower nitrogen ruler and spools cap
Many people forget that the lower thread also has its own path and its fixation points. In the spun cap there is a special spring plate, which creates the necessary resistance. If the thread does not fall under this plate or into the guide groove, it will pop out with a free loop. This is a classic mistake of beginners rushing to get started.
It is also important how the rod is inserted into the cap. The thread must be unwinded in a certain direction (usually counterclockwise for a horizontal shuttle). If you confuse the direction, the tensioner will not work correctly. It is also worth checking whether there are no dents or cracks on the spoole, which can inhibit the unwinding of the thread with jerks.
The correct sequence of filling the lower node:1. Put the spooler in the cap.
2. Then, pull the string into the side (under the spring).
3. Pull the thread until the characteristic click (for vertical shuttles).
4. Insert the cap into the machine before fixing.
Pay special attention to the purity of the spools cap. Over time, compressed down and scum accumulate there, which interfere with the normal passage of the thread. Regular brushing of this area significantly reduces the risk of stitch problems. Do not use compressed air for cleaning, as it can drive dust deeper into the mechanism.
⚠️ Attention: When removing a spooly cap, always hold it with your fingers so that it does not fall on metal parts and does not deform.
The quality of threads and the matching of the needle number
Cheap threads are the main reason for the unstable operation of even the most expensive equipment. They may be overdried, too fluffy, or have an uneven thickness in length. Such threads get stuck in the ear of the needle or break when stretched, creating the illusion of a failure of the mechanism. Use only quality threads of proven brands, designed specifically for sewing machines.
Matching the filament number to the needle number is a law that cannot be broken. A thick thread in a thin needle will get stuck, and a thin thread in a wide one will sag. The table below shows recommended combinations for different materials to avoid hinges.
| tissue | Needle number | Strand number | Features |
|---|---|---|---|
| Silk, chiffon. | 60-70 | 50-60 | Thin needle, minimal tension |
| Cotton, linen. | 75-90 | 40-50 | Standard settings |
| Jeans, coat. | 100-110 | 30-40 | Strengthened needle, tight tension |
| Knitwear | 75-90 (Jersey) | 40-50 | round-tipped needle |
The material of the thread should also be considered. Synthetic threads are more slippery and durable than cotton threads, so they require more precise tension tuning. If you use a thread with a bad twist, it will open up in the needle, creating additional friction and disrupting the balance of the upper and lower thread.
If the thread is constantly confused, try changing the coil to another, even if it is the same manufacturer. Sometimes you come across defective parties with uneven winding.
Wear of shuttle parts and synchronization
If all the settings are correct, the needle is new, and the threads are high-quality, but the hinges from the bottom continue to appear, the problem may lie in mechanical wear. The nose of the shuttle (beak) becomes dull over time or receives microscopic dentations. Instead of purely picking up the loop of the upper thread, it begins to tear or pass it, which leads to the reset of the excess length of the thread down.
Another critical parameter is the needle and shuttle synchronization. At the moment when the needle begins to rise from the lower position, the nose of the shuttle should pass strictly above the needle's eye at a minimum distance. If this gap is increased due to vibration or impact, no loop capture occurs. This is a complex adjustment, requiring removal of the covers and, possibly, the intervention of the master.
⚠️ Attention: Independent adjustment of the position of the shuttle without experience can finally bring down the machine settings. If you suspect mechanical demolition, it is better to contact the service.
Check the gap between the needle and the clamping leg. If the foot is too high or has a deformity, the tissue can rise with the needle, preventing the thread from tightening normally. In some cases, replacing the clenched foot itself helps, especially if you are working with complex tissues.
How to check the wear of a shuttle without a magnifier?
Put your finger (closely!) on the nose of the shuttle. If you feel the lead as a splinter, or see a shiny polished groove where the matte surface should be, the part requires replacement or professional polishing.
Specifics of working with knitwear and elastic fabrics
Knitwear is a separate category of materials that most often causes the formation of hinges from the bottom. The elasticity of the fabric causes it to stretch under the foot and then shrink, pulling out the extra thread. The usual straight line on the knitwear often loops, since the thread does not have time to straighten.
To solve this problem, it is recommended to use special legs, for example, a knitted foot or a walking foot, which propels the upper and lower layer of tissue evenly. It also helps to use a stabilizer (paper or flieselin), which is laid under the fabric and then torn off. This prevents the material from being pulled into the needle plate.
Don't forget the length of the stitch. For elastic fabrics, the stitch length should be slightly longer than usual (3-3.5 mm) to compensate for the stretching. Use of a type needle Stretch or Super Stretch With a cut-out in the tip also radically changes the quality of the seam on such materials.
- 🧶 Use needles with labeling Stretch or Jersey.
- 📏 Increase the length of the stitch to 3-4 mm.
- 📄 Apply a stabilizer or paper under the seam.
- 🖐️ Slightly pull the fabric behind the paws when sewing.
☑️ Diagnostics of the loop problem
Frequently Asked Questions (FAQ)
Why does the machine wind only on thick seams, and sews on thin ones normally?
This indicates that the foot is squashed when the thickening passes, and the tissue ceases to press evenly. Try putting a piece of tissue of the same thickness ("wheels") behind the foot to level the level. Also check if the needle is dulled, as it penetrates thick layers worse.
Could the cause of the hinges be a poor lubrication mechanism?
Yes, if the mechanism is "dry", it can peck at certain points, disrupting the synchrony of the needle and shuttle movement. However, more often the problem is still tension. Lubrication should be carried out according to the instructions, using only special oils for sewing machines, no more than once a year with active use.
What if the bottom thread is constantly breaking and forming nodules?
A break in the lower thread with the subsequent formation of nodules often indicates that the thread is stuck in the spools cap or there is a defect on it. Remove the spools, blow the cap, test the thread for strength. If the thread breaks easily, replace the coil.
Does the speed of rotation of the flywheel affect the appearance of loops?
Yes, if you work too fast and hard at the start, the car may not have time to form the right stitch, especially if you do not hold the thread at the beginning. Start sewing slowly, making 2-3 stitches in place or slowly twisting the flywheel with your hand to grab the bottom thread.
In 90% of cases, the problem is solved by correct filling of the upper thread and replacing the needle. Do not rush to carry the car for repairs until you rule out these simple factors.