The machine does not sew knitwear: reasons for missing stitches and solutions

The situation when your faithful sewing machine suddenly refuses to work with elastic fabrics, familiar to many craftswomen. You're trying to sew a cozy T-shirt or baby leggings, but instead of a straight stitch, you end up with chaotic gaps and loops at the bottom. This is not a breakdown of the machine, but only a signal that the settings do not correspond to the structure of the material. Knitwear, unlike woven fabrics, tends to stretch and deform under the pressure of the foot, which disrupts the standard rhythm of the mechanism.

The main problem lies in the desynchronization of needle movement and tissue advancement. When the needle goes down, the fabric can shift or fall into the needle hole, which is why the shuttle simply cannot pick up the thread. As a result skip stitch becomes systematic, damaging the product and nerves. Understanding the physics of the process will help you quickly fix the problem without contacting a service center.

Nature of the problem: physics of knitwear and sewing mechanism

To effectively deal with omissions, you need to understand how knitted fabric differs from the usual cotton or linen. In the structure of knitwear, the threads do not intertwine crosswise, but form loops that can stretch freely. Regular sewing machine needle with a sharp tip, when pierced, it does not push the threads to the side, but literally cuts them or pushes them apart with force. On elastic material, this leads to the fact that the fabric “runs away” from the needle at the moment of puncture.

The second important aspect is loop formation. To form a quality stitch, the needle must create a sufficient loop of thread that the pointed nose of the shuttle (or rotary hook) will grab at the right moment. If the fabric is too soft or too slippery (like lycra), the loop may be too small or misaligned. In this case shuttle mechanism slips past the thread and the stitch is not formed.

It is also worth considering the presser foot pressure. Pressing too hard stretches the knitwear, and after the needle passes, it contracts, deforming the stitch already made. Too little pressure results in poor tissue advancement by the rack teeth. Balance here is critical for stable operation of the node shuttle needle.

Choosing the right needle equipment

The most common reason why the machine does not sew knitwear is the use of the wrong needle. Standard needles with markings Universal or Jeans have a sharp sting designed to push apart the threads of dense fabrics. For knitwear, there are special needles with a rounded tip, which are called Stretch or Jersey. Their tip does not pierce or tear the fibers, but gently pushes them apart, passing between the threads of the fabric.

It is also important to pay attention to the size of the needle. For thin knitwear (knitwear, interlock), needles No. 70 or No. 75 are optimal. For denser brushed fabrics (footer, cashcorse), No. 80 or No. 90 are better suited. Using a needle that is too fine on thick knit fabric will cause the needle to sag and the stitch to move, causing skipping again.

Don't forget to check the condition of the needle. Even a micro-burr on the tip or slight curvature can cause a defect. Replacing the needle - this is the first action that needs to be taken when starting to work with elastic fabrics. Experienced seamstresses change the needle after each project or even while sewing long items to ensure perfect quality.

Setting thread tension and choosing a spool

The quality of the stitch directly depends on the correct balance of tension of the upper and lower threads. When sewing knits, the standard settings are often too tight, causing the seam to pull. If your machine is skipping stitches, try loosening the upper thread tension a little. This will allow the loop to straighten out and fit more easily into the hook's grip.

Particular attention should be paid to the type of thread. For elastic fabrics, polyester threads are ideal because they have their own elasticity. Cotton threads may not withstand the stretching of the fabric and burst, or, conversely, create excessive friction. Using low quality threads with pile can lead to rapid clogging of the shuttle compartment and malfunction of the mechanism.

In some cases, especially on older mechanical models, it is necessary to adjust the tension of the lower thread in the shuttle. This is done using a small screw on the shuttle cap. However, this should be done extremely carefully, having first noted the starting position.

⚠️ Attention: Before adjusting the tension screw on the shuttle cap, be sure to take a photo of its current position or make a mark with a marker. Incorrect settings can completely disrupt the operation of the shuttle unit.

Specialized presser feet and clamp

A standard foot is often too heavy or has a rough sole that slows down the sliding of the knitwear. For such fabrics there are special feet, for example, a knit foot or teflon foot. Their surface ensures perfect sliding, preventing deformation of the fabric in front of the needle. Also popular are feet with bends (rollers), which help move the material evenly.

If you don’t have a special foot, you can use a simple life hack: place a strip of thin paper (tracing paper or office paper) under the fabric. It will help the fabric pass under the foot without getting stuck, and after sewing it can be easily removed. Adjusting the presser foot pressure on the machine lever also plays a role: for thin knitwear, the pressure needs to be reduced, for thick knitwear, the pressure needs to be increased, but without fanaticism.

The needle plate is also an important element. For straight-stitch machines, there are plates with a small hole that prevent the knitted fabric from falling through. If you have a universal plate with a large hole, using stabilizer or paper becomes almost mandatory.

Algorithm of actions: step-by-step instructions for eliminating gaps

If your machine begins to act up, do not rush to disassemble it completely. Follow the logical chain (of troubleshooting), starting with the simplest and most likely causes. A systematic approach will save time and prevent unnecessary mistakes.

Check the threading first. The thread must lie correctly in each groove, especially between the tension disks. If the thread misses, there will not be the required tension. Then make sure that the needle is positioned correctly, with the flat side (flat) facing a certain side (usually back or to the right, depending on the model), and that it is not bent.

Next we move on to cleaning. Collected lint under the needle plate can interfere with thread movement and loop formation. Blow out the compartment with compressed air or gently clean with a soft brush. After this, try making a test stitch on a scrap of the same knitwear.

Table for selecting parameters for different types of knitwear

For ease of setup, we recommend using the following table. It will help you quickly navigate the choice of needle and stitch length depending on the type of material being processed.

Please note that stitch length also affects quality. A stitch that is too short can perforate the fabric and cause it to warp, while a stitch that is too long may not provide a secure fit. The optimal value for most knitted fabrics is the range of 2.5–3 mm.

Technical faults: when you need expert help

Sometimes the problem lies deeper than simple settings. If replacing the needle, thread and presser foot does not help, the gap between the needle and the hook may be broken. In modern machines this gap is minimal (fractions of a millimeter), and knocking it down leads to constant omissions. Self-adjustment requires special tools and knowledge.

The cause may also be wear on the parts of the shuttle assembly or problems with the timing (synchronization) of the rotation of the shaft and the shuttle. If you hear a knocking or squeaking sound, or if the needle hits the hook, stop using the machine immediately.

⚠️ Attention: Do not forcefully turn the handwheel if the needle gets stuck in the fabric or touches a metal part. This can lead to damage to the needle bar or the hook itself, which will require expensive repairs.

Additional tips for perfect stitching

Experienced craftsmen use various tricks to improve the quality of the seam. For example, using a starch spray or special fabric stabilizing spray helps temporarily thicken the knit, making it more like a stable fabric. After washing, the effect disappears, but the seam remains smooth.

Sewing speed also matters. On knitwear, it is better to sew at medium speed, without tugging at the fabric with your hands. Let the rack teeth themselves advance the material. Your task is to guide the fabric only slightly, without stretching it in front of the needle or pulling it behind.

Remember that each machine has its own character. What works perfectly on one model Janome, may require (fine tuning) on Brother or Toyota. Experiment with scraps, write down successful combinations of settings, and working with knitwear will cease to be torture, turning into pleasure.

Frequently asked questions (FAQ)