The third picture is from the bottom. The round part is roughly 2 inches wide while the entire piece is about 9-10 inches long.
OK, so the spring is used to keep tension on the cutter, the slot on the tube would be to eject shavings/cuttings. The cylinder looks to be tapered, so is this some type of tapering machine/tool?
is it part of a larger machine? It looks like it could be some sort of feeder, like feeding can lids on an assembly line.
Close enough. It was actually used to cap bottles of milk. You'd feed the stack of cardboard caps into the hopper and pull down on the handle. It was not part of a larger machine though.