Superior Education

Broken Threads

  • Tension
  • Needles
  • Skipped Stitches

Troubleshooting tips for broken threads and skipped stitches

If you are experiencing trouble with broken threads or skipped stitches, the following may help.

  1. Check the thread path from the spool or cone to the needle. Is it threaded correctly?
  2. Is the needle in correctly? Is it square to the face of the machine? Is the scarf to the back? Are you using the correct needle? Is it inserted all the way?
  3. Is the bobbin tension correct in relation to the top tension? Is the bobbin positioned correctly? Is there lint or other debris under the tension spring?
  4. Is the top tension correct in relation to the bobbin tension?
  5. Is the needle coming down in the center of the darning foot?
  6. If a particular thread keeps breaking, do the following: Remove the thread and put it on a different machine, make sure the correct needle size is being used and the tension is properly adjusted. If the problem follows the spool of thread, you can assume the problem is a bad spool of thread. If the thread works fine on the second machine, the problem is with the first machine and not with the thread.

Thread plies detailed
Thread construction diagram
Plies of thread
Close up image of thread plies

Tension is the term we give to the process of balancing the top and bottom threads so the machine will sew a good stitch. Here are a few scenarios to help you analyze the tension issue and remedy it.

Problem: The top thread frays.
Probable Cause: The needle is too small, the top tension is too tight, or there is a burr or rough in the thread path.

Problem: The bobbin thread shows through on the top.
Probable Cause: The bobbin tension is too loose or the top tension is too tight.

Problem: The top thread loops on the bottom.
Probable Cause: The bobbin tension is too tight or the top tension is too loose.

Problem: The top thread snaps.
Probable Cause: The top tension is too tight.

Problem: The thread gathers under the needle plate.
Probable Cause: There are two reasons why thread gathers under the needle plate. Either the top tension is too loose or the machine is threaded incorrectly, bypassing the take-up lever. It is not a thread problem. If the thread were inferior, it would simply break and not be strong enough to gather under the needle plate and jam the machine. What is occurring is that when your take-up lever raises to pull the thread back up through the fabric and form the stitching knot, it is instead simply pulling thread off the spool because there is not sufficient top tension. This situation results when the tension is set too loose, the tension disks are held apart by lint or thread debris or the thread is not pulled all the way down between the disks. The other condition occurs when the take-up lever is not pulling the thread back through at all because it is not threaded. Clean your machine regularly.

View our Troubleshooting Guide.

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