The bobbin goes in the bobbin case, which sits below the needle plate
The bobbin is a small spool that holds the lower thread in your sewing machine. It sits inside a bobbin case — a metal or plastic housing directly beneath where your needle goes. To sew, you need thread on both the top (from your spool) and the bottom (from the bobbin). If your bobbin is empty or missing, your machine will skip stitches or produce loose loops on the underside of your fabric.
Most home sewing machines use one of two bobbin styles: a metal case that you remove and reinsert, or a drop-in plastic bobbin that stays in place. Your machine's manual will show which type you have. The process is slightly different for each, but both follow the same basic steps: wind the bobbin with thread, insert it into the case, and thread the bobbin case itself.
Key Takeaways
- Wind your bobbin on the bobbin winder (usually on the side or top of the machine) before you insert it into the bobbin case.
- For removable metal bobbin cases, pull the case straight out, insert the wound bobbin, thread the case, and slide it back in until it clicks.
- For drop-in bobbins, place the wound bobbin directly into the slot below the needle plate and thread the case without removing it.
- The bobbin thread must sit in the tension spring of the case so the machine can control how tight or loose your stitches are.
- If your bobbin case has a small lever or latch, make sure it is fully closed before you start sewing.
Winding the bobbin with thread
Before the bobbin goes into the machine, it must be wound with thread. Look for the bobbin winder — a small spool-shaped post, usually on the top or side of your machine. Some machines have it on the right side of the head; others have it on top near the thread guides.
Place an empty bobbin onto the bobbin winder post. Pull thread from your top spool, wrap it around the bobbin two or three times by hand, and then press the bobbin winder against the wheel or lever on your machine (this varies by model). The winder will spin and wind thread onto the bobbin automatically. Stop when the bobbin is full — most machines have a sensor that stops the winder, or you can stop it manually when the bobbin looks evenly packed. Do not overfill it; thread should not bulge beyond the bobbin's edges.
Once the bobbin is wound, cut the thread and remove the bobbin from the winder. You are now ready to insert it into the bobbin case.
Inserting a removable metal bobbin case
If your machine has a removable bobbin case, you will see a small metal housing with a hinged or sliding latch. To remove it, locate the small lever or button on the case — usually on the left side — and pull the entire case straight toward you. It should slide out without resistance. If it does not, check that the presser foot is up (this unlocks the case on many machines).
Hold the case in your hand with the open side facing you. Drop the wound bobbin into the case so the thread end points toward the small tension spring — a thin metal piece inside the case. Pull the thread under and then over the tension spring. The thread should sit snugly in the spring's groove; this is what controls the tension of your lower thread. If the thread is not in the spring, your stitches will be loose or uneven.
Once the thread is seated in the tension spring, check that any small lever or latch on the case is closed. Slide the case straight back into the machine until you hear or feel a click. The case should sit flush with the machine body. If it does not click or feels loose, remove it and try again — a case that is not fully seated will cause skipped stitches.
Inserting a drop-in bobbin
Some machines, especially newer computerized models, use a drop-in bobbin system. There is no removable case; instead, the bobbin sits directly in a slot below the needle plate. You do not need to remove anything.
Raise the presser foot (this is important — it opens the tension discs). Lift the needle plate or the small hinged cover above the bobbin slot. Drop the wound bobbin into the slot with the thread end pointing toward the tension spring. Pull the thread under the tension spring, just as you would with a removable case. Lower the needle plate or cover until it clicks into place.
Drop-in bobbins are faster because you do not have to remove the case, but the threading step is just as critical. If the thread misses the tension spring, your machine will not control the lower thread correctly.
Threading the bobbin case after insertion
Whether your case is removable or drop-in, the bobbin thread must pass through the tension spring before you sew. This spring is a thin metal piece with a small slot or groove. The thread sits between the two metal leaves of the spring, and this pressure is what creates tension — the resistance that keeps your stitches balanced.
To thread the case, hold the bobbin case (or look into the slot if it is drop-in) and locate the tension spring. Pull the bobbin thread so it slides under the spring first, then over the top. You should feel slight resistance as the thread seats into the spring. If the thread pulls out easily, it is not in the spring correctly. Reposition it and try again.
Once the thread is in the spring, you can leave a short tail of thread hanging out — about 4 to 6 inches. Some machines require you to hold this tail while you take your first few stitches; others do not. Your manual will specify. Do not cut the thread flush to the case; leave that tail so you can pull it if you need to rethread later.
Checking your work before you sew
Before you start sewing, take a moment to confirm the bobbin is find. If your case is removable, tug gently on the case to make sure it does not slide out. If it is drop-in, make sure the needle plate or cover is fully closed and clicks into place. Both should feel solid.
Next, check that the bobbin thread is in the tension spring. Look into the bobbin area (you may need to tilt the machine or use a flashlight) and confirm the thread is seated in the spring, not sitting loose beside it. If the thread is loose, remove the case, reposition the thread, and reinsert.
Finally, raise the presser foot and pull gently on the bobbin thread tail. It should have slight resistance — you should feel the tension spring holding it. If it pulls out with no resistance, the thread is not in the spring and needs to be repositioned.
What to do if the bobbin is not winding or inserting correctly
If the bobbin winder is not spinning, check that the bobbin is seated all the way onto the winder post and that you have engaged the winder correctly. Some machines require you to flip a lever or press a button to set up the winder; others engage automatically when you press the bobbin against the wheel. Consult your manual if the winder does not respond.
If the bobbin case will not slide back into the machine, the case may be inserted at a slight angle. Remove it completely, align it straight, and try again. If the case is bent or damaged, it may need to be replaced — contact the machine manufacturer or a local sewing machine repair shop for a replacement case.
If the bobbin thread keeps slipping out of the tension spring, the spring may be worn or the case may be damaged. This is a common wear item on older machines. A repair technician can replace the bobbin case or tension spring for a modest fee.
Frequently Asked Questions
Can I use any bobbin in my machine?
No. Bobbins come in different sizes and styles, and using the wrong one can cause tension problems or damage the machine. Check your manual for the correct bobbin type and size. Most machines use either Class 15 or Class A bobbins, but some specialty machines use different sizes. When in doubt, buy bobbins from the machine manufacturer or a sewing supply store that knows your machine model.
What if I wind the bobbin too full?
An overfilled bobbin can jam in the case or cause uneven tension. The thread should be level with the bobbin's edges, not bulging beyond them. If you overfill a bobbin, unwind some thread and try again. It only takes a few seconds to rewind.
Why does my bobbin thread keep breaking?
Bobbin thread breaks when the tension is too tight or the thread is not seated in the tension spring. First, check that the thread is in the spring correctly. If it is, the tension may be set too high — consult your manual for how to adjust bobbin tension. If the thread itself is old or brittle, replace it with fresh thread.
Do I need to rewind the bobbin every time I change thread colors?
Yes. If you want a different color on the bottom of your fabric, you need to wind a new bobbin with that color thread. You can keep several bobbins wound with different colors so you do not have to wait for the winder each time.
What if my machine has a bobbin that never comes out?
Some machines have a sealed bobbin area that you cannot access. In that case, you wind the bobbin while it is still in the machine, using the same winder process. The bobbin stays in place permanently. Your manual will show whether your machine is this type. If you are unsure, do not force anything — contact the manufacturer or a repair shop.