Thank you.
So, per Candace and Christy, I will try annointing the area in Tri Flow, hoping that things wiggle and such so I can get the thread jam out, presuming there is a bit in there that I cannot see.
I am not afraid to take it apart; it is just that I cannot get the dang screws out.
Do you think that removing the whole hook assembly (marking it as Miriam suggested) and marinating it in oil or Liquid Wrench for a few days would help loosen those screws? Or Candace, was simply daubing Liquid Wrench repeatedly on to the spot enough, in your experience?
Is there a downside to Liquid Wrench? (for example, the downside to evaporust is that it can blacken things)
Miriam, thanks for your burr-advice; once I get this fixed I will very carefully take a look for smoothness to prevent future jams.