Sewing Machine: Machine locks up
Thread bunched up in the shuttle race often causes the sewing machine to lock up.
Work the needle up and out of the shuttle race by rocking the hand wheel back and forth. You may be able to remove the needle from its clamp if you're not able to raise the needle out of the shuttle race using the hand wheel. Pull the fabric away and clear the bunched thread out of the shuttle race. Clean lint and debris out of the shuttle race; they can prevent the needle from hooking the thread, resulting in thread bunching up in the shuttle race and jamming the needle. Cleaning the shuttle race may prevent the sewing machine from locking up again once you resume sewing.
If thread bunches up again immediately after you start sewing and you thoroughly cleaned the shuttle race, then needle and shuttle hook synchronization may need to be adjusted. Adjusting the needle timing typically requires service by a technician, who has special tools to synchronize the shuttle hook with the needle.
These repairs may help solve your sewing machine problem
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 needle timing
If the machine won't pick up the bobbin thread because the shuttle hook isn't synched with the needle, adjust the needle timing. Adjustment of the needle timing usually requires service by a technician. Using special tools, the technician positions the needle and loosens the shuttle drive gear set screws then adjusts the shuttle drive gear to synchronize the shuttle hook with the needle.
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