Description
Bobbin Case Tension Spring – Fits many Singers including: 401 – 403 – 404 – 411G – 421G – 431G – 500 – 503
Note: These springs are modified. The springs come from the manufacturer with the wrong bend which results in no tension.
Please see the photos below. The bobbin case on the left has a modified spring on it. See how it hugs the bobbin case?
The bobbin case on the right in each of these photos has the springs as they ship from the manufacturer. This spring as shipped would provide no tension and needs to be modified.
After modification, the spring steel is stress relieved. If this is not done, the spring will want to return to its original incorrect shape. While it did this, tension would become more and more impossible to set correctly.
As of now, I don’t plan to stock these tension springs anymore once these are gone. There’s just too much labour required to get a good working spring for the cost of them.
