Threading a bobbin is a two-step process: winding thread onto the bobbin itself, then inserting the wound bobbin into the bobbin case
Most sewing machines have a bobbin winder mounted on the top or side of the machine. You place an empty bobbin on the winder spindle, guide your thread through a tension disc on the winder, and press the bobbin against a rubber wheel or belt until the thread is wound tight. Once full, you remove the bobbin and insert it into the bobbin case — a small metal or plastic housing under the needle plate — with the thread wound in the correct direction and the thread end pulled through the tension spring.
The exact location of the bobbin winder and the direction the thread winds varies by machine model. Your machine's manual shows the specific path for your model. If you no longer have the manual, the machine manufacturer's website usually has a PDF you can read free, or you can search "[your machine model] bobbin threading" and find video demonstrations that show the exact steps for your machine.
Key Takeaways
- The bobbin winder is usually on top of the machine or on the side near the thread spools, and the thread path through the winder is specific to your machine model.
- Wind the bobbin slowly and stop as soon as it feels full or the winder disengages — overfilled bobbins jam and cause thread breaks.
- The bobbin case sits under the needle plate and holds the wound bobbin with the thread end pulled through a metal tension spring.
- Thread direction matters: the thread must wind onto the bobbin in the direction your machine's winder is designed for, or tension will be wrong and stitches will loop.
- If your machine has a drop-in bobbin (no separate case), the bobbin sits directly in a slot under the needle plate and the thread still goes through a tension spring.
Locating the bobbin winder on your machine
The bobbin winder spindle is a small metal or plastic post, usually with a rubber wheel or belt drive next to it. On most machines, it sits on the top of the machine to the right of the thread spools. Some machines mount it on the side of the machine body. A few older or specialty machines have the winder underneath or require you to remove a cover to access it.
When you place an empty bobbin on the spindle, it should sit snug and not wobble. If it falls off or spins freely, the bobbin may be the wrong size for your machine — bobbins come in different heights and diameters, and using the wrong size causes winding problems and jamming. Check your manual or the bobbin package to confirm you have the correct size for your machine.
Threading the bobbin winder
After placing the bobbin on the spindle, guide your thread from the spool through the tension disc on the winder. This disc is usually a small metal or plastic piece with a slot or groove. The thread path varies: some machines route the thread straight down into the disc, others route it from the side. Your manual shows the exact path for your model.
Once the thread is through the tension disc, wrap it around the bobbin two or three times by hand to anchor it, then hold the thread end loosely. Press the bobbin gently against the rubber wheel or belt — the wheel will grip the bobbin and begin winding. Do not hold the thread end tight; let it feed freely as the bobbin winds. If you hold it too tight, the thread will not wind evenly and the bobbin will be lumpy.
Stop winding as soon as the bobbin feels full or the winder automatically disengages. Most machines have a sensor that stops the winder when the bobbin reaches the right fullness. If you wind past that point, the bobbin becomes overstuffed, the thread jams, and you will have to unwind it and start over. Trim the thread close to the bobbin when you remove it from the spindle.
Inserting the bobbin into the bobbin case
The bobbin case is a small metal or plastic housing that sits under the needle plate. To access it, raise the presser foot (this opens the tension discs), remove the needle plate by unscrewing it or unclipping it, and lift out the bobbin case. Some machines have a drop-in bobbin design where the bobbin sits directly in a slot with no separate case — in that case, you skip the case removal step.
Place the wound bobbin into the case with the thread wound in the direction shown in your manual. Most machines wind the thread clockwise when you look at the bobbin from the right side, but this varies. The thread end should point toward the tension spring — a small metal hook or slot on the side of the case. Pull the thread end through the tension spring until it catches and holds.
Slide the bobbin case back into the machine and lock it in place. The locking mechanism is usually a small lever or clip on the case itself. Make sure the case is fully seated and the lever is in the locked position, or the bobbin will slip during sewing and cause tension problems.
Checking bobbin tension and thread path
After inserting the bobbin, raise the presser foot again to open the tension discs, then lower it to close them. This ensures the top thread is properly seated in the tension discs. Pull gently on the bobbin thread — it should have slight resistance, not pull freely. If it pulls too easily, the thread may not be through the tension spring correctly, or the spring may be bent.
Sew a test seam on scrap fabric before starting your project. If the top thread is looping on the bottom of the fabric, the bobbin tension is too loose or the bobbin is wound too loosely. If the bottom thread is looping on the top, the bobbin tension is too tight. Most machines have a small screw on the bobbin case to adjust tension, but this should be a last resort — usually the problem is the thread path, not the tension screw.
Common bobbin problems and fixes
Thread breaks while winding: The thread is caught on the spool or the tension disc is too tight. Check that the spool sits flat and the thread unwinds freely. If the disc is too tight, you may need to adjust it slightly, but most machines do not have an adjustment — the disc tension is set at the factory.
Bobbin winds unevenly or lumpy: You held the thread end too tight while winding, or the bobbin is not seated squarely on the spindle. Unwind and start over, letting the thread feed freely. Make sure the bobbin sits flat and does not tilt.
Bobbin case will not lock into place: The case may be inserted at the wrong angle or the locking lever is not fully engaged. Remove the case, check that the lever is in the open position, reinsert the case straight in, and lock the lever firmly.
Stitches loop or tension is uneven: The thread is not through the tension spring, or the bobbin is wound too loosely. Remove the bobbin case, check that the thread end is caught in the tension spring, and reinsert. If the problem continues, try a freshly wound bobbin — a loosely wound bobbin causes tension problems even if the thread path is correct.
Frequently Asked Questions
Can I use any bobbin in my sewing machine?
No. Bobbins come in different sizes and styles. Class 15 bobbins fit most home machines, but some machines use Class A, Class L, or proprietary bobbins. Using the wrong bobbin causes jamming and broken thread. Check your manual or the bobbin package to confirm the correct type for your machine.
What if my machine has a drop-in bobbin instead of a case?
Drop-in bobbins sit directly in a slot under the needle plate with no separate case. The thread still goes through a tension spring on the machine body. Wind the bobbin the same way, then drop it into the slot with the thread wound in the correct direction and pull the thread end through the tension spring before closing the needle plate.
How tight should a bobbin be wound?
A bobbin should be wound until it feels firm and the thread is smooth and even across the entire surface. It should not be so tight that the thread is stretched or the bobbin is hard to turn by hand. Most machines have a sensor that stops winding at the right point — do not override it by continuing to wind.
Why does my bobbin keep jamming?
Bobbins jam when they are overfilled, wound unevenly, or inserted incorrectly. Stop winding as soon as the bobbin feels full. Make sure the thread wound evenly and smoothly. Check that the bobbin is seated squarely in the case and the case is locked firmly in place.
Do I need to rewind the bobbin every time I change thread color?
Yes. If you switch to a different thread color, you need a fresh bobbin wound with that color. You can keep multiple bobbins wound with different colors and swap them as needed, which saves time if you sew frequently.