Thank you for your question.
I can understand your frustration with the thread jamming.
If sounds like you have a tension problem.
First I would suggest that you take the thread out of the machine and start fresh.
With the presser foot in the up position.
With the thread spool on the spool pin make sure the thread storage cut on the thread spool is facing the spool pin base.
Take the thread to the left and around the upper thread guide and forward down through the upper tension assembly and continue down and around the thread take up spring and continue up and hook the thread around the take up lever and then down through the lower thread guide into the needle thread guide and through the needle.
Remove the bobbin case clear cover and remove the bobbin.
Remove the needle plate screws and remove plate.
Check the needle plate for needle strikes and remove with an emery board until smooth.
Remove the bobbin case and check for needle strikes on the bobbin case and in the shuttle area.
Remove any lint build up in the feed dogs and reinstall all parts.
Make sure you are using the correct bobbins.
Set the upper tension control between 3 and 4 and test sew.
If that does not solve the problem please let me know in the thread link and I will help you further.
I hope this will help.
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