April 19, 2023

Sewing Machine: Why does the bobbin thread break in my sewing machine?

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

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

JC-SEW-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.

Clean the sewing machine

Find the required part specific to your product.

JC-SEW-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.

Adjust the sewing machine thread tension

Find the required part specific to your product.

Most common symptoms to help you fix your sewing machines

Choose a symptom to see related sewing machine repairs.

Main causes: faulty foot pedal, locked drive gears, wiring failure, bad drive motor…

Main causes: machine needs lubrication, internal gear failure…

Main causes: dirty shuttle race, improper thread routing, incorrect thread tension…

Main causes: dirty shuttle race, wrong thread tension, bad needle timing, damaged needle, using the wrong type of needle…

Main causes: problems with the feed dogs, setting stitch length to 0…

Main causes: disengaged clutch, broken drive belt, internal drive gear failure…

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: power supply failure, bad power cord, faulty On/Off switch…

Most common repair guides to help fix your sewing machines

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

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How to replace a sewing machine on/off switch

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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 usi…

Repair difficulty
Time required
 15 minutes or less

Effective articles & videos to help repair your 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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