Sewing machine thread tension adjustment falls into upper (top) and lower (bobbin case) adjustments.
For lower, bobbin case, adjustment follow down the page, always adjust top tension first. To return to the top of the page click on your back button.
This is a long and informative piece on tension. Put the kettle on and make yourself a nice cup of tea, then take your time to read it. It will be worth it in the end.
For many people tension adjustment is an enigma inside a riddle. The mere thought of altering the tension makes some people shudder and run for the gin. Others move toward the machine, in fear, circling a few times, muttering to themselves, before attempting to touch anything. I have known people throw sewing machines out of windows. I have seen women cry and men get mad over this one topic. Growing up in a factory full of sewing machines I soon came to learn many new words, that I passed on to eager classmates at school, all because of the humble sewing machine. I know someone—a man—who threw an industrial machine out of a third-floor window because of tension adjustment.
Well, the truth is that it is actually very easy to adjust your machine’s tension so long as you follow simple procedures. Before we start I must mention one point, although it is mainly women—over 90%—that sew, many men also sew; designers, upholsters, tailors, sail makers and so on. This adjustment pages works just as well for both sexes.