Singer Bobbin Case Tension Spring #45789

An original Bobbin Case is by far the best, so if your spring will not adjust the tension on the Bobbin Case thread (and you've checked to make sure there isn't just thread fibers caught underneath it), or if your original Bobbin Case is missing the Tension Spring altogether, then this is the replacement part. 

You will need to remove both screws to replace the Bobbin Case Spring.  Be sure to put a soft cloth or towel underneath your Bobbin Case before removing the screws so that they do not get lost (they are awfully tiny!).  If you are missing one or both screws, too - we have those available as well.