Thread the sewing machine. Adjust the tension dial in order to alter the tension. Put the dial to its lowest setting to lessen tension. Place the dial at a higher setting to increase the tension. The lower the number, the looser the tension; the higher the number, the tighter the tension.
Turn on the sewing machine. Lift the take-up lever. This will raise the lever to its highest position. To access the bobbin case, lift the bed area. Take off the case. Yank the latch. You will now be able to take off the bobbin spool.
Turn the bobbin thread tension screw clockwise with a screwdriver. This will alter the tension on the sewing machine. Put the bobbin back in its case. Press down firmly so that it locks into the machine. Put the cover back on. Switch on the sewing machine.