Check for the following matters.

• Probable cause

  Adjustment of thread tension is not performed properly.

   

  Remedy

  Position "4" on the tension dial is the standard of thread tension. Start the adjustment with "4" when adjusting thread tension. When adjusting the thread tension, change the tension dial position little by little and then check the sewing result with trial sewing.

  Refer to the instructions to learn the adjustment of thread tension.

  Instructions for adjustment of thread tension

   

  For fine tune of the thread tension, refer to the comparison chart below.

  The different type of the cover stitches and a general guideline for thread tension settings

• Probable cause

  Adjustment of the looper thread tension is improper.

   

  Remedy

  Check the position of the looper thread tension adjustment lever.
  The spring operated by the lever absorbs slack of the thread.
  Fine adjustments can be made to the looper thread tension with the looper thread tension adjustment lever.

  Refer to the instructions to learn the adjustment of the looper thread tension

  Instructions for adjustment of the looper thread tension

   

  

  (1) Looper thread tension adjustment lever
  (2) Spring

  Thread tension of back side looks bit loose?

  The stitches of cover stitch sewn with machine have elasticity not to disturb elasticity of elastic fabrics.
  The looseness of the stitch makes it possible to be stretchy.