Symptom

• The upper thread appears as a single continuous line.
• The lower thread is visible from the upper side of the fabric. (Refer to the illustration below.)
• The upper thread has tightened up, and comes out when pulled.
• The upper thread has tightened up, and wrinkles appear in the fabric.
• The upper thread tension is tight, and the results do not change even after the thread tension is adjusted.

Cause

If the lower thread is incorrectly threaded, instead of the appropriate tension being applied to the lower thread, it is pulled through the fabric when the upper thread is pulled up. For this reason, the thread is visible from the upper side of the fabric.

Remedy/check details

Correctly install the lower thread according to the following procedure.

1. Turn off the sewing machine.
    

2. Raise the needle by turning the handwheel toward you (counterclockwise).

   (1) Mark on the handwheel

    

3. Raise the presser foot lever.

   (1) Presser foot lever

    

4. Remove the bobbin cover by sliding it and lift toward you.

   (1) Bobbin cover

    

5. Remove the bobbin from the bobbin case.
   
    
6. Put the bobbin in so the thread comes out in the direction shown by the arrow.

    

   
    

   Make sure you set the bobbin so the thread unrolls in the right direction. If the thread unrolls in the wrong direction, it may cause the thread tension to be incorrect or break the needle.

    

7. Hold the end of the thread, push the bobbin down with your finger, and then pass the thread through the slit, as shown.

   (1) Tension-adjusting spring

    

   If the thread is not correctly inserted through the tension-adjusting spring of the bobbincase, it may cause incorrect thread tension.

    

8. Replace the bobbin cover. Put the projection into the bobbin race retainer groove and push closed.

   (1) Groove (2) Projection

   • Make sure that the end of the thread comes out from the cover toward the rear of the machine (as shown in the illustration).
   • Draw up the lower thread before starting sewing. Refer to “How do I draw up the lower thread?” after threading the upper thread.