Gammill recommends the use of a TOWA Bobbin Tension Gauge to ensure consistently great tension.
TOWA Bobbin Tension Gauge
The bobbin tension should be adjusted at the start of each quilt and/or whenever you change from one type of thread to another. Check the bobbin tension first and then adjust the top thread tension to make any further tension adjustments.
Gammill recommends the use of a TOWA Bobbin Tension Gauge to ensure consistently great tension. It should read between 170 and 200.
To adjust the bobbin tension, there are two screws located on the side of the bobbin case. The largest one is used to adjust the bobbin thread tension. Generally, only slight adjustments to the left (loosen tension) or to the right (tighten tension) are needed to adjust bobbin tension.
Steps to adjust tension
• Insert the bobbin in the bobbin case. The bobbin should be placed so that when looking at the bobbin it turns clockwise when the thread is pulled.
• Place the thread into the slot on the side of the bobbin case, then into the tension slot.
• Bobbin tension should be loose. If you hold the bobbin in your palm and drop your hand the bobbin case should stay in your hand but almost pick up.