Table of Contents
8 Causes of Broken Threads or Skipped Stitches
- Choose the wrong sewing thread, such as an unclear understanding of material or sewing requirements, improper bottom sewing thread coordination;
- The quality of the sewing thread itself has flaws, such as fluff, insufficient strength, loose strands, missing strands, etc.
- The size of the sewing needle is incorrect, resulting in a mismatch between the size of the sewing needle and the sewing thread;
- Damaged or defective sewing needle thread nipples or needle holes;
- The tension of the sewing thread is too large, and the tension of the sewing thread channel of the machine is not adjusted properly;
- Threading the sewing thread incorrectly or improperly operating the sewing machine;
- The eye of the sewing needle is hot, and the sewing thread does not have enough lubrication, that is, the oiling rate is not enough.
- The sewing feeding process is not smooth, or the feeding method is not appropriate.
Read More: Filament Sewing Thread
Six reasons and solutions for sewing machine jumpers
Reason 1: Can’t lead to the bottom thread
- Reason: The shuttle thread is too short, the shuttle thread is caught in the shuttle door, the needle is too high, and the shuttle cannot catch the thread loop.
- Solution: lengthen the shuttle thread, check whether the bottom thread is stuck, and eliminate it. The fastening screw of the needle bar connection shaft is loosened and the needle bar moves up. The needle bar should be lowered, and the needle should be re-aligned, and the fastening screw should be tightened.
Reason 2: The needle bar moves
- Reasons: needle bar hole, needle bar wear, needle bar connecting screw loose, needle bar displacement.
- Solution:: replace the needle bar sleeve, or choose a new needle bar, re-align the needle; and tighten the set screw.
Reason 3: One stitch is skipped after several stitches
- Reasons: The shuttle is worn, the tip of the shuttle is too blunt, and the needle of the sewing machine is too high or too low.
- Solution: Change the shuttle, adjust the height of the needle bar or the height of the needle, and re-align the needle.
Reason 4: Continuous skipping or a single stitch cannot be sewed
- Reason: The poor quality of the machine needle or the bending of the machine needle cannot produce the thread loop normally. The sewing machine needle is too high to catch the thread loop, and the sewing material and sewing machine needle are not properly coordinated. Long-term use of the shuttle, swing bed and other components are severely worn or broken.
- Solution: replace the qualified machine needle or straighten the machine needle. Adjust the needle bar or sewing machine needle height. In general, the shuttle or shuttle bed can be replaced, and overhauled if necessary.
Reason 5: Thin seams do not skip stitches, thick seams skip stitches
- Reasons: The pressure of the presser foot is not enough, the needle of the sewing machine is too thin, and the hooking mechanism and other parts are seriously worn.
- Solution: adjust the pressure of the presser foot, change the needle, replace parts, and carry out repairs.
Reason 6: Sew Thick Jumpers, Sew Thin Jumpers
- Reasons: The needle hole of the needle plate is too worn, the sewing machine needle is too thick, the bottom of the presser foot is worn, or the pressure of the presser foot is too small.
- Solution: replace the needle plate, change the fine needle, change the presser foot, change the presser foot, or adjust the pressure of the presser foot.
Read More: Thread for Sewing Machine
14 other reasons
- The threading method is incorrect. Re-thread the thread according to the “Threading Diagram”.
- The installation of the straight needle is not correct. Check the height of the needle and the facing position, so that the needle is slightly in front of the needle plate hole when it moves downward.
- The tip of the straight needle is broken or bent Replace with a new needle.
- The tip of the looper becomes blunt. Use oil stone or fine sandpaper to grind it, or replace the looper with a new one.
- The suture tension is too large or too small. Adjust the suture tension properly.
- The looper cannot catch the loop of the straight needle on the right, and the right stitch of the lower decorative thread skips. The loop of the straight needle is too small, and the amount of skipping should be increased appropriately.
- The looper cannot catch the thread loop of the left straight needle, and the left stitch of the lower decorative thread skips stitches. The thread loop of the straight needle is too large, and the amount of skipped threads should be appropriately reduced.
- The looper cannot hook the middle and left straight machine needle loops at the same time, and the middle thread and left stitches of the lower decorative thread skip stitches. Properly reduce the amount of skipped threads.
- In the middle of the back of the looper, the needle thread on the left cannot penetrate into the triangle of the knitting needle thread and the looper thread. Jump stitches in the middle of the back of the left stitch to check whether the thread passes through the thread clamp, and check the synchronous operation of the bottom thread cam. If there is any problem, press Standard adjustments.
- The improper fit between the needle and the looper Check the height of the needle bar, the synchronization between the needle and the looper, and adjust according to the standard if there is any problem.
- The improper fit between the needle and the needle guard Check the position of the needle and the needle guard.
- Improper cooperation between the needle and the stretcher needle or the position of the stretcher needle is wrong, causing the upper decorative thread to skip stitches. Check the matching size of the machine needle and the stretcher needle, and check the thread output of the stretcher thread.
- The fault caused by excessive tension of the thread take-up spring or no thread take-up spring can be solved by loosening the thread take-up spring and adding a thread take-up spring.
- There is a fault caused by a burr on the hook tip of the rotary hook, just use fine sandpaper to gently grind off the burr.
- The fault caused by excessive position error between the hook and needle can be solved by adjusting the position of the hook and needle.
- To adjust the upper and lower positions of the needle and the hook, first turn the needle to the bottom, and then slowly continue to rotate until the needle moves upward slowly. At this time, the hook tip of the hook should just move to the middle of the needle plane. That’s it.
- After completing the first step of adjustment, you can adjust the position between the needle and the tip of the hook, adjust the distance between the tip of the hook and the needle to 0~0.1mm, and then tighten the fixing bolt of the hook.