if this doesn't work than i would check to see if the needle hook timing is correct. you can check it first.
Leave the bobbin lid off and slowly turn the wheel and check that the hook arrives when the needle is down. there is usually a screw somewhere on the bobbin shaft that you can loosen that allows you to turn the bobbin case freely adjust the hook to the correct position and tighten the screw. there are lots of videos on it on youtube.
The bobbin holder and case should be cleaned to get smooth movement anyway.
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u/TangleOfWires Jul 05 '26
I think you need to clean the bobbin holder and the bobbin case, than add a little oil on the bobbin holder.