Originally Posted by
cny-bikeman
Mechanic's first rule of stuck parts: Push hard, push a little harder, stop and think.
Left-hand threaded fixed cups unscrew clockwise, looking from the drive side. I don't know what you mean by "toward the back of the frame" - it's better to tell us if you are turning clockwise or counterclockwise, and which side of the frame you are standing on.
For a left-handed thread you should be facing the drive side of the frame and be turning the bolt clockwise to loosen the fixed cup, as Sheldon explains in the section after the description of the tool.
By "towards the back of the frame" I meant: I am standing on the drive side, the frame is up with the seat tube on the bench and the rear to my right. I am turning clockwise toward the back. I am going to make an attempt at my version of the "sheldon" tool using some different and heavier components.