Ole, any idea what glue?
If it's epoxy, Loctite or something similar, or even white glue (and assuming the shutter has no soft plastic parts -- unlikely if 1950s or older vintage; heat won't hurt bakelite at all, but celluloid shutter or aperture leaves is a possibility to beware of even in early 20th century vintage shutters), remove the glass and put the board and shutter in the oven; heat to about 100-120 C (lowest setting, or "Warm" -- my oven has a setting for 200 F/95 C, but some start at 250 F/120 C), and you'll probably find the glue is softened enough to get the shutter off the board and/or unscrew the retaining ring. If not, gradually increase temperature to a maximum of 150 C -- don't go any higher than that.
That level of heat shouldn't soften or anneal any steel springs, though it's almost certain to require a CLA to deal with migrated lubricants. Nor should it harm either wood or metal lens boards, though it'll blister your skin if you aren't slightly cautious...

And it'll do no harm if the glue turns out to be something that doesn't soften with heat like celluloid househould cement or cyanoacrylate (both of the latter, BTW, respond to acetone, but that will remove paint from both wood and metal, will craze, soften, or curl most plastics, and is flammable and toxic enough to require considerable caution in use).