In The DD5 sewing machine, the bobbin case ring spring (often referred to as an anti-backlash spring or simply a bobbin case spring) plays a crucial role in regulating the bottom thread and ensuring smooth, consistent stitching.
Applies Tension: The primary function of the bobbin case ring spring is to provide tension to the bobbin thread as it unwinds. Just like the tension assembly for the top thread, the bobbin thread needs a specific amount of resistance to interlock correctly with the top thread and form a balanced stitch. The spring creates this resistance.
