Causes

Solutions

Upper Thread Breaks

• Incorrect threading
• Knots or twists in thread
• Tension too tight
• Damaged/old needle
• Needle too small

• Re-thread machine properly
• Replace thread
• Reset bobbin and top thread tension
• Replace needle
• Use correct needle for thread and application

• Bobbin case incorrectly threaded
• Bobbin case incorrectly inserted
• Bobbin does not turn smoothly in bobbin case
• Lint in bobbin case
• Bobbin tension too tight

• Remove bobbin and re-thread with bobbin turning clockwise
  
• Remove and re-insert bobbin case
• Check that bobbin case and bobbin are in “round”; replace if necessary
  
• Clean bobbin case and surrounding machine area
• Check and reset bobbin tension

• Thread tension too tight
• Needle damaged
• Needle wrong size
• Sewing machine out of adjustment

• Reset top and bobbin tension
• Replace needle
• Use correct needle size
• Have sewing machine adjusted for timing; hook to needle clearance; needle bar height

• Needle too small
• Tension too tight
• Damaged thread

• Increase needle size
• Reset tension
• Replace thread

• Thread not in top tension
• Machine incorrectly threaded
• Top tension too loose
• Burr on hook mechanism

• Re-thread machine with presser foot “up”
• Re-thread machine incorporating take-up lever
• Reset top tension
• Remove burr

• Wrong needle size
• Incorrect threading
• Upper tension too loose
• Operator pulling fabric
• Bobbin wound unevenly

• Ensure correct needle for fabric & thread
• Unthread machine and carefully re-thread
• Reset lower and upper thread tension
• Check presser foot pressure
• Rewind bobbin

• Excessive stitch length
• Needle point is blunt
• Excessive thread tension
• Fabric is too soft
• Thread displacement – too much thread in a small area
• Fabric not feeding

• Decrease stitch length
• Change needle often
• Check bobbin and upper tension
• Use stabilizer
• Decrease field density; scale embroidery designs; increase stitch length
• Check presser foot, needle plate, feed dogs