Why does a sewing machine loop from below and how to fix it yourself

Problem with looping the thread from below - one of the most common malfunctions of sewing machines, which both beginners and experienced craftsmen encounter. Symptoms manifest themselves in different ways: sometimes the thread forms tangles under the fabric, sometimes the stitches are uneven, and sometimes the machine completely stops sewing normally. The reasons may lie either in simple incorrect refueling or in serious mechanical failures.

Many people immediately run to the service center, but in 80% of cases the problem can be solved on their own in 10–30 minutes. The main thing is to correctly diagnose the source of the problem. In this article we will look at all possible reasons, from basic to complex, and we will give step-by-step instructions for eliminating them. You will also learn how to avoid looping again in the future.

If your machine suddenly starts to loop, don't panic. First check the obvious: the correct threading, the condition of the needle and the quality of the thread itself. Most often, the root of evil lies here. But if simple manipulations don’t help, you’ll have to dig deeper.

1. Incorrect threading is the most common cause.

Errors when threading the upper or lower thread occur in 60% of looping cases. Even experienced seamstresses sometimes miss the thread tensioner or insert the bobbin incorrectly. This is especially true for electronic models Janome, Brother or Singer, where the thread path is more intricate than that of mechanical machines.

What to check first:

• 🔹 Upper thread: has it been passed through all guides (including tensioner and compensation spring)? On models Brother NV-1500 People often forget to thread the thread through the metal hook above the needle.
• 🔹 Bottom thread: Is the bobbin inserted correctly into the hook? It must rotate counterclockwise (when viewed from above). On typewriters Janome Memory Craft The bobbin is secured with a latch - make sure it clicks.
• 🔹 Thread direction: The bobbin case usually has an arrow on it indicating how the thread should wind up. If you mix up the direction, looping is guaranteed.

How to thread correctly:

1. Raise the needle to the highest position (turn the handwheel on yourself).
2. Pass the upper thread through everything guides, including the tensioner (on most machines it is located at the top right).
3. Lower the foot - this will automatically raise the thread take-up and lock the thread.
4. Insert the bobbin into the hook, pull the thread through the slot and bring it back (under the presser foot).

⚠️ Attention: On typewriters Singer Heavy Duty and Juki TL-2010Q There is an additional tensioner on the bobbin case. If it is not adjusted, the thread will loop even when threaded correctly.

2. Problems with the needle: blunt, bent or the wrong size

The needle is a consumable item, but many people forget to change it. A dull or bent needle not only breaks the thread, but also causes looping. This is especially noticeable when working with dense fabrics (jeans, leatherette) or when using thick threads (for example, for quilting).

Signs that the problem is in the needle:

• 🔸 The car starts to loop after puncturing thick tissue (for example, several layers of jeans).
• 🔸 The thread breaks or gets stuck in fabric when sewing.
• 🔸 On the wrong side are formed large loops, and the stitches are uneven.

How to check and replace the needle:

1. Take out the needle and inspect it against the light: if the tip curved or blunted, replace.
2. Check the markings: for thin fabrics (silk, chiffon) use needles 70/10, for cotton - 80/12, for jeans - 90/14 or 100/16.
3. Make sure the needle is inserted all the way and secured with a screw. On models Pfaff and Husqvarna Viking the needle holder has a special groove - the needle must fit into it flat side back.

Fabric type	Recommended needle size	Needle type
Silk, chiffon, organza	60/8 or 70/10	Universal or for thin fabrics
Cotton, linen, chintz	80/12	Universal
Jeans, canvas, leather	90/14 or 100/16	For jeans or leather
Knitwear, stretch	75/11 or 80/12	With a rounded end (ballpoint)

3. Thread and needle mismatch: why is it important?

Even if the needle is new, but does not match the thickness of the thread, looping cannot be avoided. For example, a thin thread (№40) in a thick needle (90/14) will dangle in the lug, creating uneven tension. And vice versa: thick thread (№60) in a thin needle (70/10) will cling to the fabric and tear.

How to choose thread and needle:

• 🧵 For thin fabrics (silk, cambric) use threads №60–80 and needles 60/8–70/10.
• 🧵 For medium fabrics (cotton, linen) - threads №40–50 and needles 80/12.
• 🧵 For dense fabrics (jeans, tent) - threads №30–40 (polyester) and needles 90/14–100/16.

Please note thread material:

• 🔴 Cotton threads fluffier and can get stuck in the shuttle. They are best used for manual work or on old mechanical machines.
• 🟢 Polyester threads (for example, Gütermann or Mettler) are smoother and less loopy.
• 🔵 Overlock threads Not suitable for regular sewing machines - they are too elastic and will skip stitches.

What to do if the thread constantly breaks?

If the thread breaks while sewing, check:

1. Condition of the needle (blunt or bent).

2. Correct filling (are there any snags on the edge of the machine).

3. Upper thread tension (too much tension leads to breakage).

4. Thread quality (cheap threads often have thickenings and knots).

5. Condition of the shuttle (burrs or dirt can chafe the thread).

4. Violation of thread tension: how to adjust

Incorrect tension is the second most common cause of looping. If upper thread is too weak, she cannot pick up the lower one, and it is pulled to the front side, forming loops. If bobbin thread is too tight, the upper thread cannot grab it, and loops are formed from below.

How to check tension:

1. Take two threads of different colors (for example, the top one is red, the bottom one is blue).
2. Sew a test stitch on a piece of fabric.
3. Look where the threads intersect:
   • 🔴If The top thread pulls the bottom thread to the right side → loosen top tension.
   • 🔵 If the bottom thread pulls the top thread inside out → strengthen top tension.
   • 🟣 If both threads intertwined in the middle → tension is adjusted correctly.

How to adjust tension on different models:

• 🔧 On mechanical typewriters (for example, seagull or Podolsk) tension is adjustable screw on the bobbin case (small screwdriver included).
• 🔧 On electronic machines (Brother CS-6000i, Janome 2200XT) Upper thread tension is adjustable digital disk (usually from 0 up to 9).
• 🔧 On industrial machines (Juki DDL-8700) the tension of the lower thread is adjustable screw on the shuttle.

Thread different colors of thread|Sew a test seam|Check thread intersection|Adjust top tension|Check bottom tension (if necessary)-->

⚠️ Attention: On typewriters Bernina and Pfaff yes automatic tension adjustment. If you manually changed the settings, reset them to factory defaults (Menu → Reset → Default Settings).

5. Contamination of the shuttle and mechanism: cleaning and lubrication

Dust, thread fragments and fabric lint accumulate in the shuttle mechanism, interfering with the free movement of the thread. This results in uneven tension and looping. This is especially true for machines that have not been cleaned for a long time or have been used to work with fleecy fabrics (fleece, terry cloth).

How to clean the shuttle:

1. Turn off the machine and remove the bobbin case.
2. Remove thread and lint from the shuttle compartment using soft brush (you can use an old toothbrush).
3. Wipe the mechanism dry cloth (do not use wet wipes!).
4. Lubricate moving parts 1–2 drops of machine oil (only if this is provided for in the instructions!). On models Janome and Brother Lubrication is required every 6–12 months.

What to do it's impossible:

• ❌ Use vacuum cleaner - it can damage plastic parts.
• ❌ Lubricate the mechanism vegetable oil or WD-40 - this will cause thickening and breakage.
• ❌ Clean the shuttle needle or scissors - the surface may be scratched.

On machines with a horizontal shuttle (for example, Brother Innov-is) especially a lot of lint accumulates in the area under the needle. If you don't clean it every 3-6 months, the looping will become chronic.

6. Mechanism breakdowns: when repairs are indispensable

If you've tried all of the above and the machine is still looping, the problem may be mechanical failure. Most often they break:

• 🔩 Shuttle mechanism - wear or displacement of the shuttle (typical of old machines Chaika-134 or Podolsk-142).
• 🔩 Thread take-up - if it does not rise all the way, the thread will not be caught correctly.
• 🔩 Tension regulator — over time, the spring stretches and ceases to hold tension.
• 🔩 Needle holder - if it is bent, the needle will move and the stitches will turn out uneven.

How to diagnose a breakdown:

• 🔧 Check does the shuttle move evenly?. If it “sticks” or knocks, repair is required.
• 🔧 Look, Does the thread take-up lift up all the way?. If not, the spring may have broken.
• 🔧 Try flashing without fabric (raise the presser foot and start the machine). If the thread loops even in the air, there is a mechanical problem.

In these cases, it is better to contact the service. However, you can fix some problems yourself:

• 🔧If the shuttle is displaced, it can be carefully adjusted with a screwdriver (but only if you are confident in your abilities!).
• 🔧If Tensioner spring has weakened, it can be tightened (on old machines).

7. Prevention: how to avoid looping in the future

To prevent the problem from recurring, follow these simple rules:

• 🧼 Clean the machine after each major project (or once every 1–2 months with regular use).
• 🔄 Change the needle every 8–10 hours of work (or after sewing thick fabrics).
• 🧵 Use high quality threads (for example, Gütermann, Mettler, Madeira). Cheap threads often have uneven thickness, which leads to looping.
• 📖 Keep the instructions at hand - it contains tensioning and care recommendations for your model.
• 🛠️ Once a year, spend preventive examination: lubrication, tension adjustment, shuttle check.

If you sew often thick fabrics (jeans, leather, tarpaulin), recommended:

• Use needles for jeans (90/14–110/18) with a reinforced tip.
• Increase upper thread tension by 1–2 divisions.
• Sew on reduced speedto reduce the load on the mechanism.

⚠️ Attention: If you sew elastic fabrics (stritch, cooler), use special elastic thread in a bobbin (for example, Maxi-Lock Stretch). Regular thread will break and loop due to the stretching of the fabric.

FAQ: Frequently asked questions about sewing machine looping

The machine loops only when sewing knitwear. What's the matter?

Knitwear is a stretchy fabric and requires special settings:

• Use needle with rounded end (ballpoint or stretch).
• Reduce upper thread tension by 0.5–1 division.
• Sew on special foot for knitwear (it has a Teflon coating).
• Use elastic thread in a bobbin (for example, Woolly Nylon).

It loops only at high speed. What to do?

This is a sign shuttle mechanism wear or low thread tension. Try:

• Increase the upper thread tension by 1–2 notches.
• Clean and lubricate the shuttle.
• Sew at medium speed - if the looping disappears, it means that the mechanism requires repair.

On industrial machines (Juki, Typical) this problem is often solved adjustment of needle and hook synchronization (needs a master).

The machine loops after replacing the bobbin. Why?

Probable reasons:

• bobbin wrong brand (for example, plastic instead of metal).
• Thread on bobbin unevenly wound (there are thickenings or nodes).
• bobbin not inserted correctly into the hook (check the direction of rotation!).
• On the bobbin case tension spring weakened.

Solution: Rewind the thread onto the bobbin evenly, check the compatibility of the bobbin with your machine model.

Can you use overlock thread in a sewing machine?

No, this will lead to looping and thread breakage. Overlock threads:

• More elastic (designed for fabric stretching).
• Have different twist structure, which is why they are poorly captured by the shuttle.
• Often thinner standard sewing threads, which leads to weak tension.

Exception: some polyester threads (for example, Maxi-Lock) are suitable for both machines, but need to be checked on a test patch.

After cleaning the shuttle, the machine began to loop even more. What's wrong?

Possible errors:

• you the shuttle was assembled incorrectly (check if it is skewed).
• Lubricated the mechanism wrong oil (use only machine oil for sewing machines).
• Damaged lower thread tensioner when cleaning (check if the spring is loose).
• Left pile or thread inside the mechanism (need to repeat cleaning).

Solution: Re-disassemble the shuttle following the instructions and make sure that all parts are in place.