Why does lower looper keep breaking - Sewing Machines

Could be several reasons.

First, check that the tension is not set too tight.

Usually, however, it is because it is threaded incorrectly. Sergers are very finicky creatures who demand threading perfection or they refuse to operate.

When a thread breaks, it is best to remove ALL the threads and rethread from the beginning (ah, painful as it is, it is usually less frustrating in the end). ALWAYS raise the presser foot when threading. This releases the tension disks so the thread will seat in the disk. ALWAYS give each thread an extra little tug when going through the tension disk to confirm it is seated--sometimes it will make a little "pop" sound.

Third, ALWAYS thread each thread in the order instructed in the owner's manual. Generally, the upper looper is threaded first, then the lower looper is threaded second. The lower looper thread finishes by laying Over the top of the upper looper before being pulled toward the back of the presser foot.

Confirm that every thread is following the correct path. Any skipped or loops around guides will interfere with correct operation.

Set all the tension dials to the midway point and test your serger.

Just as an FYI--it took me one entire day of constantly rethreading before I finally got my serger to work the first time. Believe me, it came close to growing wings and flying out the window more than once!!!

If it continues to be a problem, you may need to take it for service.

Make It Handmade Threading Your Serger or Overlocker

Serger Problems

Make It Handmade How to Thread Your Serger Out of Order

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Probably need a adjustment, you may have to have the looper checked