[Hallicrafters] SX-71 how to undo "stuck" screws

[RJB]

Good morning to all...

im the guy who keeps asking SX-71 questions, and i have another. The last
remaining issue i have with my ebay SX-71 is a sloppy bandspread dial drive
string - in order to tighten it i need to remove the black metal panel with
the band calibrations painted on it. Problem is i can not undo all the
retaining screws - some are slotted others are phillips-head, and all but
one are stuck fast :(

I assume that Hallicrafters really torqued their screws up, as i have had
problems undoing other screws on this radio. I do not want to risk a
skidding screwdriver tearing up the nice black dial; and drilling the screws
out is not a viable option, and i do not want to apply heat as it may damage
the dial markings.

Does anyone have a secret method for loosening up old halli screws??

thanks in advance for any help

Bob Bennett, Maple Vly, WA