4th Deadly Sin:
Sewing with the wrong bottom tension
Have you tried a new needle, checked the thread path, adjusted your top tension and still can’t get a good stitch? It could be that your bobbin tension is too tight or too loose. If you think about the tension setting of your top and bottom thread as a tug-of-war, you can begin to see how to adjust your tension to get that perfect stitch. If top thread is breaking it would most likely be due to too tight top tension (see deadly sin 2) however, if your tension is loose up top and still breaking, it’s a good idea to check to see if bobbin tension is too tight. Bird nesting underneath may be a sign that your bobbin tension is too loose.
Adjusting your bobbin tension is as simple as turning the screw on your bobbin a quarter turn.
To assist you in achieving that perfect bobbin tension we have a video on how to use the TOWA bobbin guage for longarm/midarm machines and a great education article which details how to get the right amount of bobbin tension.