HOW TO BALANCE THREAD TENSIONS
Different threads and fabric types can cause irregular tension. Before making adjustments determine closely that the machine is threaded correctly and the proper needle is being used.
Balanced Needle Thread Tension
The needle thread and bobbin thread should interlock in the center of two layers of the fabric in straight seams.
Adjusting Bobbin Thread Tension
Test the bobbin thread tension by first holding the end of the bobbin thread and suspending the bobbin case as illustrated. Then, flick your wrist once or twice to check the drop of the bobbin case.
qIf the thread comes out of the bobbin case continuously,
| and the bobbin case keeps falling, the bobbin thread | |
| tension is too loose. | |
w | Make a slight adjustment by turning the screw clockwise | |
with the small screwdriver. | ||
| ||
| q To tighten |
If the thread does not come out of the bobbin case at all, the bobbin thread tension is too tight.
Make a slight adjustment by turning the screw counter clockwise with the small screwdriver. w To loosen
The bobbin tension is set correctly if the bobbin drops but then stops.
Adjusting Needle Thread Tension
qw
r 
w
qe
Needle thread tension is too tight:
If the bobbin thread r shows through on the right side of the fabric q and it feels bumpy, loosen the needle thread tension by turning the dial to the left.
qRight side of the fabric w Wrong side of the fabric e Needle thread
r Bobbin thread
Needle thread tension is too loose:
If the needle thread e loops on the wrong side of the fabric w, tighten the needle 
thread tension by turning the dial to the 
right.
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