How about a dial face for a diaphragm type low pressure differential gauge? An older gauge designed to display pressure in psi would usually be marked in 1/8 or 1/16 divisions.
I do not know enough about WWII aircraft systems to say what in particular it might have been used for. Maybe the difference between the air pressure inside a fuel tank or pressurized cabin vs ambient atmospheric pressure, or the drop in MAP through a carburetter, or some such?? Otherwise did they use this type of gauge for engine systems control/monitoring? Some gauge variants are called capsule type diaphragm differential pressure gauges, or alternatively - diaphragm type capsule differential pressure gauges.