Sewing Machine: Bobbin thread breaks

A dirty shuttle race, improper thread routing or incorrect thread tension can break the bobbin thread.

Unplug the sewing machine and check thread routing according to guidelines in your owner's manual. Reroute the thread correctly if necessary.

Also, check thread tension settings because incorrect thread tension can break the bobbin thread. Set thread tension according to the guidelines in your owner's manual.

Clean the shuttle race because lint and debris buildup can bind up the bobbin and break the bobbin thread.

sewing machine

These repairs may help solve your sewing machine problem

Clean the sewing machine

Clean the sewing machine

Clean lint and debris from the shuttle race every 3 months because it often attracts lint and dust. Clean the feed dogs at the same time because they also attract lint and dust. Clean those areas more often when using the sewing machine regularly. Oil the sewing machine after cleaning.

Adjust the sewing machine thread tension

Adjust the sewing machine thread tension

Tight upper thread tension causes skipped stitches. Reduce the upper thread tension when the sewing machine skips stitches. Adjust lower thread tension as necessary to balance with the upper thread tension to create perfect stitches.

Symptoms common to all sewing machines

Choose a symptom to see related sewing machine repairs.

Main causes: machine needs lubrication, internal gear failure
Main causes: disengaged clutch, broken drive belt, internal drive gear failure
Main causes: problems with the feed dogs, setting stitch length to 0
Main causes: faulty foot pedal, locked drive gears, wiring failure, bad drive motor
Main causes: dirty shuttle race, wrong thread tension, bad needle timing, damaged needle, using the wrong type of needle
Main causes: power supply failure, bad power cord, faulty On/Off switch
Main causes: lack of lubrication, lint buildup, worn drive belt, faulty drive motor
Main causes: thread bunched up in the shuttle race, bad needle timing, internal drive gear failures
Main causes: dirty shuttle race, improper thread routing, incorrect thread tension
Repair guides common to all sewing machines

These step-by-step repair guides will help you safely fix what’s broken on your sewing machine.

April 1, 2015
By Lyle Weischwill
How to replace a sewing machine drive motor

If the drive motor on your sewing machine runs roughly or doesn't run at all, you can replace it in about 30 minutes using these simple steps.

Repair difficulty
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How to replace a sewing machine on/off switch

If the sewing machine is completely dead, replace the On/Off switch using these 6 steps.

Repair difficulty
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How to replace a sewing machine drive belt

You can replace a broken sewing machine drive belt in about 15 minutes.

Repair difficulty
Time required
 15 minutes or less
Articles and videos common to all sewing machines

Use the advice and tips in these articles and videos to get the most out of your sewing machine.

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How to use a multimeter to test electrical parts video
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