I think they're used for getting little tiny bits of meat out of lobstah claws.
Seriously, if they came from the estate of someone known to be an engraver, it's possible that they were used to consistently mark the inside and outside of borders, sort of a fixed divider. The spacing seems to be slightly different on each set of three, but proportionally the spacing appears to be very close to the same on each tool. They'd be very useful if that was their purpose.
It's also possible that they were used for removing rivets or other small nail-shaped parts from watches or the like. They look sort of like miniature hand-made automotive ball joint removers.
Just a couple of guesses, I really don't know.