SteveF I pull my dry vac pumps apart about every 5 years, check them, clean them and reassemble them with a dry graphite powder lube.
doing this has its little challenges but I am yet to see any wear in the vanes in 15 years.
the inner of a dry vac pump is a hard carbon block with angled slots in it.
in each of these angled slots is a hard carbon blade about 5mm thick.
as they wear the dust is a lubricating carbon (graphite?) dust.
what will bring them undone is an oil leak into them gumming up the dry low drag environment they usually experience.
if moving a prop actually does break the vac pump blades I wouldn't crucify the miscreant because in reality the blades would have been so worn that they were about to break anyway.
one reason why YOU dont service these is because some of the parts are quite delicate and and are very easily ruined.