Threading the bobbin is the first step before you sew

The bobbin holds the lower thread in your Kenmore machine. To thread it, you wind thread onto an empty bobbin using the machine's winding mechanism, then place the wound bobbin into the bobbin case below the needle plate. The whole process takes about two minutes once you know where each part is and what order the steps go in.

Most Kenmore machines use one of two bobbin styles: a plastic drop-in bobbin that sits directly under the presser foot, or a removable bobbin case that you pull out to load. Your machine's manual will tell you which one you have, but you can also look under the presser foot — if you see a small metal or plastic cup that comes out, you have a removable case. If the bobbin sits flat in a visible slot, you have a drop-in style.

Key Takeaways

  • Wind thread onto an empty bobbin using the bobbin winder on the right side of your machine before you load it into the machine.
  • For a drop-in bobbin, place the wound bobbin directly into the slot under the presser foot with the thread tail pointing toward the tension spring.
  • For a removable bobbin case, insert the wound bobbin into the case, thread the tail through the tension slot, then slide the case back into the machine.
  • The bobbin thread should pull with slight resistance when you tug it by hand — if it spins freely, the tension is too loose.
  • If your machine skips stitches or the lower thread breaks, the bobbin is usually wound too tight or threaded incorrectly.

Winding thread onto the bobbin

Start with an empty bobbin and a full spool of thread on the spool pin at the top of your machine. Place the empty bobbin onto the bobbin winder spindle — this is a small metal post on the right side of the machine, usually near the top. Push the bobbin all the way onto the spindle until it clicks or sits flush.

Bring the thread from the spool down and wrap it around the bobbin two or three times by hand, going clockwise. Then guide the thread through the bobbin winder tension disc — a small slot or notch on the winder assembly — and hold the thread tail loosely in your hand. Press the foot pedal or press the start button (depending on your model) and let the machine wind the bobbin. The winding will stop automatically when the bobbin is full, or you can stop it by releasing the pedal.

Cut the thread close to the bobbin when winding stops. Do not overfill the bobbin — if thread is piled higher than the bobbin's edge, it will not fit into the case or slot properly and will cause tension problems.

Loading a drop-in bobbin

A drop-in bobbin sits in a visible slot directly under the presser foot. Raise the presser foot to release the tension, then look at the slot under the needle. You will see a small metal or plastic spring clip on one side of the slot.

Hold the wound bobbin so the thread tail points toward that spring clip. Drop the bobbin into the slot and let it sit flat. The thread tail should rest against the spring — this is the bobbin tension. Pull the thread tail gently; it should move with slight resistance, not spin freely. If it spins without resistance, the bobbin is not seated correctly or the tension spring is not touching the thread.

Once the bobbin is in place and the thread is under tension, bring the thread tail up and to the left, then tuck it under the presser foot. Lower the presser foot to lock the bobbin in place. You are now ready to thread the upper thread and begin sewing.

Loading a removable bobbin case

A removable bobbin case is a small metal or plastic cup that you pull straight out from under the presser foot. Raise the presser foot, then locate the case — it usually sits on the left side under the needle plate. Pull the case toward you or lift it straight out, depending on your machine model.

Hold the wound bobbin with the thread tail pointing up and to the left. Drop the bobbin into the case so it sits flat in the bottom. The bobbin should not move or rattle when you shake the case gently.

Now thread the bobbin thread through the tension slot. Look for a small notch or slot on the side of the case, usually marked with an arrow or line. Pull the thread tail and guide it into that slot so it sits in the tension spring. Pull the thread gently — it should move with slight resistance. If it spins freely, the thread is not in the tension slot.

Slide the bobbin case back into the machine. It should click or seat firmly. Bring the thread tail up and to the left, then tuck it under the presser foot. Lower the presser foot. You are now ready to thread the upper thread.

Checking bobbin tension

Bobbin tension is correct when the thread pulls with noticeable resistance but does not break when you tug it. Hold the bobbin (still in the case or slot) by the thread tail and pull down gently. The thread should not spin freely, and it should not come out of the tension slot.

If the thread spins without resistance, the bobbin is not threaded through the tension slot, or the tension spring is not touching the thread. Remove the bobbin, check that the thread is in the tension slot, and try again.

If the thread breaks when you pull it, the bobbin is wound too tight or the tension is set too high. Wind a new bobbin with less tension — wrap the thread around the bobbin fewer times before threading through the winder tension disc, or wind more slowly.

Troubleshooting common bobbin problems

If your machine skips stitches or the lower thread breaks during sewing, the bobbin is usually the cause. First, remove the bobbin and check that it is wound evenly and not overfilled. Rewind a new bobbin if the old one looks lumpy or has thread piled on one side.

Next, remove the bobbin case (if your machine has one) and clean out any lint or thread scraps using a small brush. Lint buildup in the case or slot prevents the bobbin from sitting correctly and throws off tension. Reinsert the bobbin and check that the thread is in the tension slot.

If the machine still skips stitches after you have reloaded the bobbin, the problem may be with the upper thread or needle instead. Check that the upper thread is threaded correctly and that the needle is inserted straight and not bent.

Frequently Asked Questions

What size bobbin does a Kenmore machine use?

Kenmore machines use either Class 15 bobbins (the most common plastic drop-in style) or Class A bobbins (metal, used in older machines with removable cases). Check your machine's manual or look at an old bobbin to see which size you need. Most fabric and craft stores sell both types.

Can I use a bobbin from a different brand in my Kenmore?

Yes, as long as it is the same class size. A Class 15 bobbin from Brother or Singer will work in a Kenmore machine that uses Class 15 bobbins. The brand does not matter, only the size and style. Check your manual to confirm which class your machine uses.

Why does my bobbin keep coming loose?

A loose bobbin usually means it is not seated all the way into the slot or case. For drop-in bobbins, push it down firmly until it sits flat. For removable cases, slide the case all the way in until you hear a click. If the bobbin still moves, the slot or case may be worn and need replacement.

How tight should I wind the bobbin?

Wind the bobbin until it is full but not overstuffed — thread should not pile higher than the bobbin's edge. The winding tension should be firm but not so tight that the bobbin becomes hard to turn. Most machines have an automatic stop that prevents overwinding, so let the machine do the work and do not force it.

Do I need to rewind the bobbin before every project?

No. Rewind the bobbin only when it runs out of thread during sewing. A full bobbin holds enough thread for most small to medium projects. If you are doing a large project with a lot of stitching, wind a second bobbin ahead of time so you can swap it out if the first one empties.