Originally Posted by
Hemlock
The Singer Featherweight Shop website
http://thefeatherweightshop.com/ has a lot of wonderful videos on how to maintain/repair your featherweight ("Schoolhouse" on the menu). I highly recommend them! They are also on YouTube
https://www.youtube.com/watch?v=x3-qEvw_V0w -- this is the one that walks you through getting thread from behind the bobbin case. When you take the throat plate off, you may see thread and lint, even broken needle points, if it wasn't cleaned before you bought it, near the feed dogs as well. I used 3-in-1 PENETRANT (NOT 3-in-1 oil! Use only sewing machine oil. ) to free up the bobbin holder on mine. I also bought the maintenance kit from their online shop when it was on sale to get their recommended grease, and the oil bottle with a fine tip.
Thank you all for your suggestions. I was able to turn the jammed bobbin case base after soaking several days in tri-flow oil I was on the verge of removing the entire hook assembly, when it finally turned and I was able to remove the piece of thick upholstery thread from between the bobbin case base and the hook assembly. I'm not sure that removing the hook assembly would have helped, so glad I was patient enough to give it a good oiling over several days. At first I was using sewing machine oil that I purchased from my local sewing machine dealer. Then I used the tri-flow oil, not sure if that made the difference, but I will be using tri-flow from now on exclusively. Good luck to those of you that have had this problem, just turn machine up on end with bobbin assembly on top and keep filling the area with tri-flow oil!