I thought this one would never come out. Lightrace fixed cup installed in the frame for 70 years. And it's French thread. Grabbing the flats in the vise didn't work. The flats would deform slightly and the frame would jump out of the vise.

So on to Sheldon's method. 1/2" bolt, nut, and washers. Socket wrench with a 16" handle on the non-driveside. Top tube under the armpit. Pulled up and it came loose with only moderate effort. The power of friction!