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TROUBLE SHOOTING FOR LOCKSTITCH
PRESSER FOOT FAULTS
Presser foot jams up
Presser foot jams down
Presser foot doesn't lift high enough
Presser foot lifts too high
Presser foot doen't hold material
STITCHING FAULTS
Miss stitching
Stitches misaligned
STITCH LENGTH FAULTS
Reverse stitch too small
Reverse stitch too big
Forward stitches too small
Forward stitches too big
Stitches vary in size
SEWING MACHINES
Possible Fault
Presser bar clamp jamming
Presser bar requires oiling
Presser bar clamp jamming
Presser bar requires oiling
Top of presser bar catching the lower section of
the pressure screw
Knee lift stop incorrectly set
Lifting bar on the presser foot arm set too high
Knee lift stop incorrectly set
Lifting bar on the presser foot arm set too high
Knee lift stop incorrectly set
Lifting bar on the presser foot arm set too high
Presser foot loose
Feed dog too low
Insufficient pressure on presser bar
Materials incompatible
Possible Fault
Too much needle thread tension
Hook timing out of line
Hook point too far from needle
Needle bar height incorrect
Needle size to small
Needle size too big
Threads size incorrect for needle size
Incorrect type of needle point
Check spring tension too heavy
Check spring timing incorrect
Needle plate hole too small
Threaded incorrectly
Damaged hook point
Hook too short
Needle touching side of needle hole
Needle damaged
Needle point damage
Materials causing needle to move to the left or
right of the weave
Possible Fault
Reverse mechanism misaligned
Reverse mechanism misaligned
Feed dog too low
Pressure set to lightly
Feed timing incorrect
Needle bar timing incorrect
Presser foot loose
Feed dog loose
Adjust the maximum stitch control setting
Feed dog too high
Feed dog timing incorrect
Feed dog too low
Presser foot loose
Insufficient pressure on presser foot
Needle bar timing incorrect
Possible Remedy
Remove the bar and rectify the cause of the
jamming
Lightly oil presser bar and mechanism
Remove the bar and rectify the cause of the
jamming
Lightly oil presser bar and surrounding
mechanism
Tighten the pressure screw 2 or 3 complete turns
Reset knee lift motion stop
Rest lifting bar
Reset knee lift motion stop
Rest lifting bar
Reset knee lift motion stop
Rest lifting bar
Tighten presser foot
Reset feed dog height
Tighten pressure
Upgrade to top feed or walking foot machine
Possible Remedy
Reduce needle tension
Retime hook
Adjust hook lateral position
Adjust needle bar height
Replace needle with one of a larger size
Replace with a smaller needle
Change to a thread size compatible to the
materials and size of needle
Replace needle with correct type of point and size
Adjust check spring timing and strength
Adjust check spring timing
Enlarge needle plate hole
Thread machine correctly
Replace hook
Replace hook
Enlarge needle hole
Replace needle
Replace with new needle
Use correct size and type of needle for materials
adjust tensions as necessary
Possible Remedy
Realign reverse mechanism
Realign reverse mechanism
Adjust height of feed dog
Adjust presser foot pressure
Adjust feed timing
Adjust needle bar timing
Tighten presser foot
Tighten feed dog
Reset the maximum stitch setting on the stitch
length control(in the centre of control)
Lower feed dog
Retime feed dog
Adjust feed dog height
Tighten presser foot
Increase pressure on the presser foot
Retime needle bar
17:8
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