Upper thread tightened up

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.

image1

(1) Lower side of fabric

(2) Lower thread visible from upper side of fabric

(3) Upper thread

(4) Upper side of fabric

(5) Lower thread

 

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).

    image

    (1) Mark on the handwheel

     

  3. Raise the presser foot lever.

    image

    (1) Presser foot lever

     

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

    image

    (1) Bobbin cover

     

  5. Put the bobbin in so the thread comes out in the direction shown by the arrow.

     

    image
     

    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.

     

  6. Lightly hold down the bobbin with your right hand as shown (A), guide the thread through the slit (B).

    image

    (1) Slit

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

     

  7. While lightly holding down the bobbin with your right hand (A), guide the thread through the slit (B) and lightly pull it with your left hand (C).

    image

     

  8. While lightly holding down the bobbin with your right hand (A), continue guiding the thread through the slit with your left hand (B) Then, cut the thread with the cutter (C).

    image

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

    image (1) Tension-adjusting spring

     

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

    image

    (1) Groove
    (2) Projection

    Start sewing after threading the lower and upper thread. When sewing gathers or darts, you can draw up the lower thread by hand so that some thread will be left over. Refer to “How do I draw up the lower thread?”.

If your question was not answered, have you checked other FAQs?

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If you need further assistance, please contact Brother customer service:

Related Models

JA1450NT, JA20, JK17B

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