Examples of thread tension adjustment

For correct overlock stitching, the looper threads and needle threads should be as described below.

• The upper looper thread and the lower looper thread are intertwined at the edge of the fabric.
• There is no looping in the needle threads on either the surface or the reverse of the fabric.

If the overlock stitching does not sew correctly, adjust the thread tension.
Move the thread tension dial by a half or quarter scale marking, and then continue sewing.

Left needle thread forms loops on reverse of fabric

A : Reverse B : Surface C : Left needle thread

Increase the tension of the left needle thread.


 

Right needle thread forms loops on reverse of fabric

A : Reverse B : Surface D : Right needle thread

Increase the tension of the right needle thread.


 

Fabric puckers

A : Reverse B : Surface C : Left needle thread D : Right needle thread

Reduce the needle thread tension of the left needle thread first  , then of the right needle thread  .


 

Upper looper thread visible from reverse of fabric

A : Reverse B : Surface E : Upper looper thread F : Lower looper thread

Increase the tension of the upper looper thread, reduce the tension of the lower looper thread, or adjust both thread tensions.


 

Lower looper thread visible from surface of fabric

A : Reverse B : Surface E : Upper looper thread F : Lower looper thread

Reduce the tension of the upper looper thread, increase the tension of the lower looper thread, or adjust both thread tensions.


 

Large loops because upper looper thread or lower looper thread extends past edge of the fabric

A : Reverse B : Surface E : Upper looper thread F : Lower looper thread

Increase the tension of the upper looper thread and the lower looper thread.


 

Stitching puckers

A : Reverse B : Surface E : Upper looper thread F : Lower looper thread

Reduce the tension of the upper looper thread and the lower looper thread.