Screw, Bobbin Case Tension Adjustment
This tiny screw is the one that regulates the bobbin tension in the bobbin case. Looking at the bobbin case with open end facing down and the screws toward you, it is the one on the right. It is different from the attachment screw on the left and they are not interchangeable.
Fits original Singer and most aftermarket bobbin cases for the 221, 222, and 301.
