Start with the simplest fixes first

Most sewing machine problems stop the needle or jam the thread, and most of those problems come from three things: a bent or dull needle, lint buildup, or thread wound wrong. Before you call a repair person, spend ten minutes checking these three. A new needle costs a dollar. A cleaning takes five minutes. Threading takes two minutes. If one of these fixes it, you save the cost of a service call.

The machine will tell you what is wrong by how it fails. If the needle breaks, it is usually bent or inserted backward. If the thread keeps breaking, the needle is dull or the tension is too tight. If the machine jams or makes a grinding sound, lint is blocking the feed dogs or the bobbin area. If stitches skip, the needle is the wrong size for your fabric, or it is inserted wrong. Start by identifying which of these is happening, then follow the matching fix below.

Key Takeaways

  • A bent, dull, or backward needle causes most thread breaks and skipped stitches, and replacing the needle is the first thing to try.
  • Lint buildup in the bobbin area and under the feed dogs jams the machine and makes it grind; clean these spots with a small brush after every project.
  • Thread wound on the bobbin backward or wound too tight causes tension problems and thread breaks.
  • Rethreading the machine with the presser foot up opens the tension discs and usually fixes thread-related problems.
  • If the machine still does not work after checking the needle, cleaning lint, and rethreading, the internal timing or tension assembly may need professional repair.

Replace the needle the right way

The needle is the part that wears out fastest and causes the most problems. A needle that is bent even slightly will break thread, skip stitches, or break itself. A needle that is dull will shred thread and leave holes in fabric. Most machines need a new needle every eight to ten hours of sewing, or sooner if you sew heavy fabric like denim.

To replace the needle, first raise the presser foot all the way up — this opens the tension discs and lets the needle come out easily. Turn the handwheel toward you until the needle is at its highest point. Loosen the needle clamp screw (usually on the right side of the needle) by turning it counterclockwise with a screwdriver. Pull the old needle straight down and out. Insert the new needle with the flat side facing the direction your machine manual shows — this is usually toward the back or toward the left, depending on your machine. Push the needle all the way up into the clamp, then tighten the screw firmly. The needle should not wiggle.

Buy needles that match your fabric weight. Use size 60/8 or 70/10 for lightweight fabrics like cotton voile or silk. Use 80/12 or 90/14 for medium-weight cotton and linen. Use 100/16 or 110/18 for heavy fabrics like denim or canvas. Using the wrong size needle will cause skipped stitches and thread breaks no matter how well the machine is adjusted.

Clean lint from the bobbin area and feed dogs

Lint collects under the feed dogs (the metal teeth that move fabric forward) and inside the bobbin case. This buildup jams the machine, makes it grind, and can break the needle. You should clean these areas after every project, especially if you sew cotton or fleece, which shed more lint than other fabrics.

Raise the presser foot and the needle to the highest point. Remove the bobbin case — most machines have a small latch or screw that holds it in. Use a small brush (a soft toothbrush works) to brush lint out from under the feed dogs and from inside the bobbin case. Brush toward you so lint falls out, not deeper into the machine. Do not use a vacuum, because the suction can pull out small springs or damage internal parts. Do not use a toothpick or metal tool, because you can scratch the metal parts and cause problems later.

Once the area is clean, put the bobbin case back in and make sure it clicks or locks into place. If you see lint again after just one project, the machine may have a deeper blockage, and you should take it to a repair person.

Rethread the machine with the presser foot up

Thread that breaks or shreds often breaks because the thread is not seated in the tension discs. The tension discs are two metal plates inside the machine that grip the thread and control how tight the stitch is. When the presser foot is down, the discs are closed and grip the thread. When the presser foot is up, the discs open and release the thread so you can thread the machine.

Many people thread the machine with the presser foot down, which means the thread never actually enters the tension discs. The thread just sits on top of them, and the machine pulls it too tight, breaking it. To fix this, raise the presser foot all the way up, then unthread the machine completely. Pull the thread out of every guide and the needle. Now thread it again from the top, making sure the thread passes through each guide and sits between the tension discs. You should feel a slight resistance when you pull the thread down through the tension area — that is the discs gripping it. Thread the needle last. Now lower the presser foot and sew a test seam. The thread should break less often and the stitches should look more even.

Wind the bobbin correctly and check tension

The bobbin is the small spool that holds thread underneath the fabric. If the bobbin is wound too tight, too loose, or backward, the bottom thread will break or the tension will be uneven. Most machines come with plastic bobbins, and you wind them using the bobbin winder on the machine.

To wind a bobbin, place an empty bobbin on the bobbin winder pin (usually on the top or side of the machine). Place the thread spool on the spool pin and guide the thread through the bobbin winder tension guide. Tie the thread around the bobbin or hold it against the bobbin as it starts to wind. Press the foot pedal or push the start button. The bobbin will wind until it is full, then stop automatically. The bobbin should be wound evenly and firmly, but not so tight that the plastic dents. If the bobbin is wound in a lump or cone shape, the tension guide is not set right, and you should check your manual for the correct setting.

Once the bobbin is wound, insert it into the bobbin case with the thread tail coming out to the left (or the direction your manual shows). Pull the thread tail through the small slot in the bobbin case. If the bobbin is inserted backward or the thread is not in the slot, the tension will be wrong and stitches will skip.

Check for a bent or damaged presser foot

The presser foot holds fabric flat against the feed dogs so the machine can move it forward evenly. If the presser foot is bent, cracked, or damaged, fabric will not feed straight and stitches will skip or bunch. You can see a bent presser foot by looking at it from the side — it should be level and parallel to the needle plate.

To replace the presser foot, raise the needle and presser foot to the highest point. Most presser feet have a small screw or latch on the back. Loosen or release this, and the foot will drop off. Slide the new presser foot into the holder and tighten the screw or latch. Make sure the foot is level and does not tilt to one side. Different fabrics and stitches need different presser feet — a ballpoint foot for knits, a walking foot for thick fabrics, a zipper foot for zippers — so if you are sewing a new type of fabric and stitches skip, try a different presser foot designed for that fabric.

Know when to take the machine to a repair person

If you have replaced the needle, cleaned the lint, rethreaded the machine, and checked the bobbin, and the machine still does not work, the problem is inside the machine. The timing may be off, the tension assembly may be damaged, or a spring or gear may be broken. These repairs need someone with training and the right tools.

Take the machine to a repair person if it makes a grinding or clicking sound that does not go away after cleaning, if the needle breaks every time you sew even with a new needle, if the thread breaks constantly even after rethreading, or if the machine does not move fabric forward at all. Bring the machine with a sample of thread and fabric so the repair person can test it. Most repair shops charge a diagnostic fee (usually fifteen to forty dollars) to figure out what is wrong, and then they tell you the cost to fix it before they start work.

Frequently Asked Questions

Why does my needle keep breaking?

A needle breaks because it is bent, inserted backward, or the wrong size for your fabric. It can also break if you are pulling fabric toward you while sewing instead of letting the feed dogs move it. Replace the needle, check that the flat side faces the right direction, and use the correct needle size for your fabric weight. If a new needle still breaks on the first seam, the machine may have internal damage and needs repair.

What does it mean when stitches skip?

Skipped stitches usually mean the needle is dull, bent, or inserted wrong. They can also mean the needle is the wrong size for your fabric, or the thread is not threaded through the tension discs. Replace the needle first, then rethread the machine with the presser foot up. If stitches still skip, try a different needle size or a different presser foot designed for your fabric type.

How often should I clean my sewing machine?

Clean the bobbin area and feed dogs after every project, especially if you sew cotton or fleece. Use a small soft brush to remove lint. A deeper cleaning of the entire machine (removing side panels and cleaning internal parts) should happen once a year if you sew regularly, or every two years if you sew occasionally. Your machine manual will show which parts you can safely remove.

Can I use any bobbin in my machine?

No. Bobbins come in different sizes and styles, and using the wrong bobbin can jam the machine or cause tension problems. Check your machine manual or the bobbin case itself to find the correct bobbin type. Most modern machines use plastic bobbins, but some older machines use metal bobbins. Bring your machine or bobbin case to a fabric store if you are not sure which type you need.

Why is my thread breaking on the bottom?

Bottom thread breaks because the bobbin is wound too tight, inserted backward, or the thread is not in the slot in the bobbin case. Rewind the bobbin and make sure it is wound evenly and firmly but not dented. Reinsert the bobbin with the thread tail coming out to the left and pull the thread through the slot. If the thread still breaks, the bobbin case may be damaged and need replacement.