Problem

Causes

Solutions

Upper Thread Breaks

● Incorrect threading

● Knots or twists in thread

● Tension too tight

● Damaged/old needle

● Needle too small

● Rethread machine properly

● Replace thread

● Reset bobbin and top thread tension

● Replace needle

● Use correct needle for thread and application

Bobbin Thread Breaks

● 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

Skipped Stitches

● 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

Frayed Stitches

● Needle too small

● Tension too tight

● Damaged thread

● Increase needle size

● Reset tension

● Replace thread

Thread Loops on Bottom

● Thread not in top tension

● Machine incorrectly threaded

● Top tension too loose

● Burr on hook mechanism

● Rethread machine with presser foot "up"

● Rethread machine incorporating take up lever

● Reset top tension

● Remove burr

Irregular Stitches or Malformed Stitches

● Wrong needle size

● Incorrect threading

● Upper tension too loose

● Operator pulling fabric

● Bobbin wound unevenly

● Ensure correct needle for fabric & thread

● Un-thread machine and carefully rethread

● Reset lower and upper thread tension

● Check presser foot pressure

● Rewind bobbin

Fabric Puckers

● 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