How to Replace Bobbin Case Spring

How to replace the bobbin case brake spring

After the post a few days ago on how to check for proper tension on the bobbin brake spring (also called bobbin tension spring or bobbin anti-backlash spring) I have had several inquiries about how to replace one that has flattened out.

Pic 1 shows a small probe (in this case a ball point pen - but could be toothpick, small screwdriver, hair pin or similar instrument) inserted between the bobbin spring and the bobbin case - pry the spring gently up and it will pop out of the slots it is secured into.

How to replace a bobbin case spring | Longarm-Tech | Delighting discerning quilters by helping them optimize the performance of their longarm machines & frames.

Pic 2 shows the new bobbin spring oriented with the bobbin case, and the arrows show the tabs on the bobbin spring and the slots in the bobbin case where the tabs will be inserted.

How to replace a bobbin case spring | Longarm-Tech | Delighting discerning quilters by helping them optimize the performance of their longarm machines & frames.

Carefully place the new bobbin spring in the bobbin case (make sure the center of the spring is higher than the outer section) - gently push the tabs of the spring into the slots of the bobbin case with a small probe (pic 3).

How to replace a bobbin case spring | Longarm-Tech | Delighting discerning quilters by helping them optimize the performance of their longarm machines & frames.

Pic 4 - the center circle of the new spring (the pictures are from a new Cerliani M-class bobbin case) should be around 5mm (3/16") above the floor of the bobbin case - see arrows.

How to replace a bobbin case spring | Longarm-Tech | Delighting discerning quilters by helping them optimize the performance of their longarm machines & frames.

Last - use a probe to check to ensure that 1: the spring is thoroughly inserted into the slots, and 2: the spring center is higher than the outer edges – this video will show you how to test.

Quilt on!


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