Singer 404 bobbin issue
I recently got a Singer 404, and so far, I love it. However, there is an issue I didn’t expect.
It came with one metal bobbin, and it has worked wonderfully for me. However, I wanted to get some more bobbins, so I chose the plastic Class 66 ones because I thought they would be fine.
However, when I tried the new bobbin, it seemed like my Singer was having a tension issue. I compared the seams using the old metal bobbin and the new plastic one, and apparently, the seam with the plastic bobbin is loose, which seems like a lower tension issue.
I’m not sure what could be causing the problem. Is it because the metal bobbin is heavier? Is there a way to fix this without buying more metal bobbins?
I would greatly appreciate any suggestions. Thank youu!