Longarm Thread Tension Diagnosis — Fixing Top and Bobbin Thread Problems
Longarm Thread Tension Diagnosis — Fixing Top and Bobbin Thread Problems
Thread tension is the most common longarm troubleshooting issue. Here’s how to diagnose and fix top thread and bobbin thread tension problems systematically.
Linda’s Electric Quilters Expert Guide
Tension Symptom Diagnosis
| What You See | Cause | Fix |
|---|---|---|
| Loops on top surface | Top tension too loose OR bobbin too tight | Increase top tension first; check bobbin last Top First |
| Loops on back surface | Top tension too tight OR bobbin too loose | Decrease top tension first Decrease Top |
| Top thread breaking | Tension too high, needle too small, bad rethread | Lower tension, go up needle size, rethread Rethread |
| Bobbin thread breaking | Bobbin inserted incorrectly, case burr | Remove, reinsert bobbin; inspect case Check Case |
| Skipped stitches | Dull needle, speed too fast | Change needle, slow down Change Needle |
▶ The Golden Rule Adjust one variable at a time. Change only top tension OR bobbin — not both. Test after every adjustment. Most tension issues are top tension; touch the bobbin case last.
How do I check if my bobbin tension is correct?
Hold the bobbin case by the thread and gently shake it. It should drop slowly — not freely (too loose) and not hold completely still (too tight). This gives a baseline; fine-tune for your specific thread weight and quilt sandwich combination.