Looping thread under the needle plate when trying to perform a straight line most often indicates a desynchronization of the thread drive or an incorrectly installed needle, which makes it impossible to create a high-quality needle. shuttle-stitch. If the top thread is not captured by the shuttle’s nose, the machine begins to skip stitches or create tangles from below, requiring immediate stop and check the refueling. The correct formation of the machine connection depends on the exact interaction of the needle, threads and fabric, as well as on the correct adjustment of tension.
To eliminate defects, it is necessary to make sure that the needle is inserted to the end with a flat side to the holder, and the thread is carried through all the guides under the foot in the lowered state. Violation of the refill sequence or the use of a dulled needle leads to rupture of tissue fibers and the formation of unaesthetic puffs. In professional sewing, the quality of the line determines the durability of the product, so ignoring the first signs of failure can lead to a breakdown of the mechanism.
Direct line and basic connections
The basis of any sewing process is straight-line, which is used for grinding parts, performing finishing operations and laying assemblies. The quality of this seam directly depends on the length of the stitch, which is selected depending on the density of the material: for thin fabrics, the length of 2-2.5 mm is optimal, and for dense ones - 3-4 mm. Incorrect choice of length leads either to excessive perforation of the fabric, or to weak fixation of the seam.
When performing a straight stitch, it is important to monitor the position of the foot and the pressure on the fabric to avoid shifting the layers. Use of the tissue with different heights of teeth allows you to work with delicate materials without damaging the structure of the fibers. The stability of the flywheel speed also affects the uniformity of the stitches.
To prevent the tissue from being tightened into the needle hole when working with thin materials, put a strip of paper under the seam, which is then easy to remove.
There are several variations of the basic compound, each of which has its own application characteristics depending on the type of product:
- 🧵 Strike seam in the air A classic compound where the allowances are smoothed in different directions to reduce the thickness.
- 🧵 Sewing stitch - a strong connection without a mark, where one passage completely covers the cut of another, denim fabric.
- 🧵 Stitching suture. decorative or functional overlay of one part on another with the laying of a line on the front side.
⚠️ Attention: When switching from thick tissue to thin or vice versa, be sure to adjust the pressure of the foot, otherwise the lower layer of tissue will move faster than the upper, causing a skew of the seam.
Zigzag and elastic compounds
Seam zigzag It is a universal tool for processing slices, performing elastic joints and decorative finishes. Unlike straight stitching, zigzag allows the seam to stretch along with the fabric, which is critical when working with knitwear, a cooler or a jersey. The width and pitch of the zigzag are customized individually: a narrow and frequent zigzag is used to mark the cut, and for an elastic connection - a wide one with a large step.
When performing elastic connections, special needles with a rounded tip, designated by the marking, must be used. Stretch or Jersey. Sharp needles for woven fabrics can damage the structure of the knitwear, leading to the formation of holes along the seam. The tension of the top thread when performing a zigzag often requires relaxation compared to a straight line.
The zigzag technique requires smooth rotation of the flywheel when lowering the needle in extreme positions to avoid breaking the thread. Modern machines automatically adjust the speed at the moment of turning the needle, but on mechanical models this process is controlled by the operator.
Overwheel imitations and secret seams
Many household cars are equipped with a function pseudooverlockIt simulates the treatment of the edge with an overturned paw. This seam simultaneously grinds the parts and processes the cut, preventing the threads from falling. For high-quality execution, a special foot with a guide side that holds the edge of the fabric on weight, allowing the zigzag threads to bend the cut.
The secret seam It is designed for inconspicuous stitching of the bottom of trousers, skirts or sleeves. The secret of this seam is that the needle only captures a few threads of the underlying tissue, leaving the stitch virtually invisible from the front side. For its implementation, a special foot with a vertical limiter is used.
The effectiveness of overlay imitations depends on the correctness of filling the bottom thread and setting the width of the stitch:
- 🪡 Three-stranded seam - imitation of an overlock, where the needle makes a stitch over the edge, and the shuttle forms a loop.
- 🪡 Elastic secret seam - variation for knitwear, allowing the seam to stretch without breaking the threads.
- 🪡 Decorative marking - use of colored threads to create a contrasting edge on products in the style of boho or denim clothing.
⚠️ Warning: Never attempt to perform a secret seam on tissues that are too thick or stiff without first checking, as the needle may bend or break, damaging the mechanism.
Table settings for different tissues
The correct selection of machine parameters is the key to a quality seam. Below is a help table to help determine the optimal settings for common materials. Remember that the data may vary depending on the particular machine model and thread thickness.
| tissue | Needle type | Stitch length (mm) | Strand tension |
|---|---|---|---|
| Silk, chiffon. | Microtex (60-70) | 1.5 - 2.0 | Weak (2-3) |
| Cotton, linen. | Universal (80-90) | 2.5 - 3.0 | Average (4-5) |
| Jeansa, coat. | Jeans (100-110) | 3.0 - 4.0 | Strong (6-7) |
| Knitted, knitted. | Stretch/Ballpoint (75-90) | 2.5 - 3.0 (zigzag) | Average (4-5) |
| Skin, suede | Leather (90-100) | 3.0 - 3.5 | Medium/strong |
Using an inappropriate needle or improper tension leads to defects that are difficult to fix after the fact. For example, too much tension on a thin fabric will collect the seam into the harmonica, and weak on a dense one will leave a looping thread from below.
☑️ Check before sewing starts
Diagnosis and correction of defects
Even experienced seamstresses face stitch quality issues that are often solved by simple adjustment. Rotating from below usually indicates a weak tension of the upper thread or improper filling. If the thread breaks, it is worth checking the sharpness of the needle and the presence of burrs on the needle plate.
Skipping stitches is often associated with using a blunt or curved needle, as well as the wrong combination of needle number and thread thickness. In some cases, it is necessary to replace the clamping paw with a more suitable for a particular type of seam.
The main symptoms and methods of their elimination:
- 🔧 Fabric assembly - Reduce the tension of the upper thread and reduce the pressure of the foot.
- 🔧 Understrand break Check the spooler cap for the presence of pile and dust, lubricate the mechanism.
- 🔧 Double line. Make sure the thread is properly inserted into the tension spring.
Secrets of the Perfect Line
To obtain a professional result, use high-quality threads that do not contain nodes and thickenings. Cheap threads can leave the pile in the mechanism, which will lead to malfunctions in the machine. Also regularly clean the shuttle area with a soft brush.
Frequently asked questions
Why does the machine miss stitches on knitwear?
The most common reason is to use a regular needle instead of a needle with a rounded tip (Stretch). A regular needle tears the knitted fibers rather than pushing them apart, which leads to missing the grip of the bottom thread. Also check if the thread is too tight.
What length of stitch to choose for sweeping?
For temporary sweeping of parts, it is recommended to set the maximum length of the stitch, usually 4.0-5.0 mm. This will make it easy to remove the thread after fitting or the main strike without damaging the fabric.
Can I make a jean on a regular typewriter?
Yes, you can, but you need to install a special needle for jeans (marking). Jeans, size 100 or 110) and use of strong threads (No. 40 or No. 30). The sewing speed at thickening of the seams (for example, the intersection of the side seams) should be reduced, helping the flywheel with the hand.
What if the bottom thread is constantly getting tangled?
This is a classic sign of improper filling of the upper thread. Remove the thread completely and refuel, be sure to raise the leg (to open the tension discs). Also check if the spool is inserted correctly into the cap.
The quality of the seam depends on 80% of the condition of the needle and the correctness of filling the thread, and only 20% of the machine settings. Always start your diagnosis with a needle replacement.