The bobbin goes in the bobbin case, which sits under the needle plate
The bottom thread on your sewing machine lives in a small metal or plastic holder called the bobbin case, which sits directly under the needle plate (the flat metal piece the fabric rests on). To thread it, you first wind thread onto a bobbin — a small spool that holds the bottom thread — then insert that bobbin into the case and guide the thread through a tension spring. The whole process takes about two minutes once you know where everything is.
Most machines have the bobbin case in the same location: drop the needle to its lowest point, remove the needle plate by unscrewing it or unlatching it, and you will see the bobbin case sitting in a small compartment underneath. Some machines have a removable bobbin case that you pull straight out; others have a fixed case built into the machine. Check your manual to see which type you have — it changes how you load the thread.
Key Takeaways
- Wind thread onto the bobbin using the bobbin winder on the side or top of your machine before you insert it into the bobbin case.
- The bobbin case sits under the needle plate and holds the bottom thread; you access it by removing the needle plate.
- Thread the bobbin by pulling the thread through the tension spring slot in the bobbin case, then leaving a 3- to 4-inch tail hanging out.
- If the bottom thread breaks, bunches, or loops, the bobbin is usually wound too loose, inserted wrong, or threaded incorrectly through the tension spring.
Wind the bobbin before you insert it
Your machine comes with empty bobbins — small plastic or metal spools. Before you can use one, you have to wind thread onto it using the bobbin winder, which is usually a small wheel or spindle on the side or top of your machine. Place an empty bobbin on the winder, guide the thread from your top spool around the bobbin a few times by hand to anchor it, then press the foot pedal or turn the hand wheel to wind the thread onto the bobbin automatically.
Wind until the bobbin is full but not overstuffed — it should look like a full spool of thread, not a lumpy ball. Most machines have a sensor that stops the winder automatically when the bobbin is full. If yours does not, watch carefully and stop when the bobbin feels firm and the thread is wound evenly. A bobbin that is too loose will cause the bottom thread to break; one that is too tight can jam the bobbin case.
Remove the needle plate and locate the bobbin case
Lower the presser foot (the metal arm that holds fabric down) and turn the hand wheel to drop the needle all the way down. This is important because the needle needs to be out of the way when you remove the needle plate. Look under the presser foot for the needle plate — it is the flat metal or plastic piece with a hole for the needle and usually has markings for stitch width.
The needle plate is held on by one or two screws, or sometimes by a latch or clip. Unscrew it or release the latch and lift it straight up. Underneath, you will see the bobbin case — a small metal or plastic holder that looks like a tiny boat or shell. Some bobbin cases are removable (you pull them straight out); others are fixed to the machine and do not come out. Your manual will tell you which type yours is.
Thread the bobbin through the tension spring
If your bobbin case is removable, take it out and hold it in your hand. If it is fixed, you will thread it while it sits in the machine. Either way, the process is the same: take the thread from your wound bobbin and guide it into the tension spring — a small metal slot or hook on the side of the bobbin case. Pull the thread firmly so it sits snugly in the spring; you should feel a slight resistance.
Once the thread is in the tension spring, let it wrap around the bobbin case if there is a groove or channel for it to follow. Leave a tail of thread hanging out — about 3 to 4 inches. This tail is important: it helps the machine catch the top thread and form the first stitch. If you cut the thread too short, the machine may skip stitches or not start properly.
Insert the bobbin case back into the machine
If you removed the bobbin case, slide it back into the compartment under the needle plate. It usually sits at an angle and clicks or locks into place — you will feel it snap. If it is a fixed case, you are already done with this step. Either way, make sure the bobbin case is seated firmly and the thread tail is still hanging out where you left it.
Replace the needle plate by screwing it back on or latching it down. Make sure it is tight so it does not shift during sewing. Lower the presser foot and you are ready to thread the top of the machine and start sewing. If the bottom thread breaks or the stitches look wrong after you start, the most common cause is that the bobbin was wound too loose or the thread did not sit properly in the tension spring.
Troubleshoot if the bottom thread is not working right
If the bottom thread breaks while you are sewing, the bobbin is usually wound too loosely. Rewind a new bobbin, making sure the thread is tight and even as it winds. If the bottom thread bunches or loops, the thread may not be sitting in the tension spring correctly — take out the bobbin case and re-thread it, making sure you hear or feel the thread click into the spring.
If the thread still does not work after you have reloaded the bobbin, check that the bobbin itself is not damaged or bent. A bent bobbin can catch on the case and cause the thread to fray or break. If the bobbin looks fine but the problem continues, the tension spring itself may be bent or the bobbin case may need cleaning — lint and thread bits can jam the mechanism. A soft brush or compressed air will clean it out.
Frequently Asked Questions
How tight should the bobbin be wound?
The bobbin should be wound firmly and evenly, like a store-bought spool of thread. It should not be so loose that you can see gaps between the thread layers, and not so tight that it bulges or feels hard. If you are unsure, wind it on medium tension and stop when the bobbin feels full but still slightly springy.
What if my bobbin case does not have a tension spring?
Some older or specialty machines have a different design. Check your manual for the exact threading path — the thread may wrap around a peg or guide instead of a spring. The principle is the same: guide the thread through the correct path and leave a tail hanging out.
Can I use a bobbin from a different brand machine?
No. Bobbins are machine-specific and come in different sizes and styles. Using the wrong bobbin can jam the case or cause the thread to wind unevenly. Buy bobbins made for your machine model — your manual lists the correct type, or you can ask at a fabric or sewing supply store.
Why does my bottom thread keep breaking?
The most common cause is a bobbin wound too loosely. Other causes include a bent bobbin, thread not seated in the tension spring, or lint buildup in the bobbin case. Try rewinding the bobbin first, then check that the thread is in the tension spring, then clean the case with a soft brush.
Do I have to remove the needle plate every time I change the bobbin?
If your bobbin case is removable, you can usually pull it out without removing the needle plate — just lift it straight up. If your case is fixed, you will need to remove the plate to access it. Check your manual to see which type you have.