Thanks Craig.
I didn't try any WD40, as the phillip screw heads are flanged and I didn't think the oil would get to the threads... won't hurt to try, anyway.
Tightening to break a thread grip is a different approach. If the threads of the screw are protruding beyond the female threads they're engaged in, those protruding threads could be a problem too. This is why a lot of hex screws snap off. Maybe I could get the penetrating oil to the other side... if I can find access.
Working the threads forward then back would certainly help.
Jerry
