FAQ : DOUBLE CHAINSTITCH

  • --Needle is broken
  1. The specification of the needle is not suitable for the materials
  2. The needle is wrongly assembled.
  3. One of the adjustmens of the needle/looper/thread wiper is incorrect.
  4. The pulling roller (VCL) does not cooperate with the feed dog.
  5. The presser foot is rubbing against the needle.
  6. The feed dog height is not enough.
  7. The height of the needle bar is too low.
  8. The thread is too thick or having bad quality.
  9. The needle doesn’t go through the needle plate hole correctly.
  • --Noise
  1. The feed dog has touched the needle plate.
  2. The VB14 and VB07 are not assembled well.
  3. The thread wiper runs into the feed dog.
  4. The left/right positions of the VD31 are incorrect.
  5. The preeser foot doesn’t stay on the needle plate flatly and well.
  • -Skipped stitch
  1. The needle size is not right.
  2. The needle is bent or has burrs.
  3. The timing of needle/looper/thread wiper is incorrect.
  4. The position relation between needle and needle guard is incorrect.
  5. The quality of thread is poor.
  6. The threading quantity of VF18 is not enough.
  7. The timing of VE06 is incorrect.
  8. The pressure of thread control knob is incorrect.
  9. The speed of the puller is incorrect.
  10. The position of VK13 is incorrect.
  11. Incorrect threading.
  12. The timing relationship of looper is incorrect.
  13. The clearance between the needle guard and the needle is too wide.
  14. Improper pressure adjustment of the presser foot.
  • -Thread broken
  1. The needle is bent or uneven.
  2. Poor quality of the thread or uneven thread.
  3. The looper rubs against the needle.
  4. The timing of needle/looper/thread wiper is incorrect.
  5.  The threading quantity of VF18 is not enough.
  6. The thread control knob is too tight.
  7. Incorrectly threading.
  8. Improper adjustment of the looper thread.
  9. Inappropriate left and right adjustments of the needle/looper/thread wiper.
  10. Sewing starts before the fabrics are fed completely under the presser foot.
  11. The needle doesn’t go through the needle plate hole correctly.
  • --The sewing is not smooth
  1.  The height of the feed dog doesn’t match the fabrics.
  2. Improper pressure adjustment of the presser foot.
  3. The timing adjustment of the puller is inappropriate.
  4. The lower surface of the presser foot is worn or not smooth.
  5. The feed dog is worn or doesn’t keep horizontally.
  6. The chosen needle is not suitable for the sewing fabrics.
  7. There are burrs on the gear puller
  8. The pressure of the puller is too strong or too weak.
  9. The clearance between the upper and the lower puller is not correct,
    or the two puller are not parallel to each other.
  10. The roller VCL33 doesn’t function well.
  11. Inappropriate pressure adjustment of the thread control knob.
  12. Inappropriate pressure adjustment of the rear puller.
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