Featherweight 221 Bobbin Case Comparison of Original to Aftermarket

We are comparing a vintage original bobbin case with an 80 dollar aftermarket bobbin case, to a pair of 18 dollar bobbin cases. This is a real time video, so you will see actual diagnosis and repair times.

[@theunknownchef5825]

Wonderful video, nice to see how you measured them and diagnosed the problem with the final one.
A little hard to see exactly where you were filing…was it on the curve of the upper piece?
Thanks