I didn't find any other markings except the letters "A" "B" "C" & "D" next to the thumb screws. I attached some more pictures with the devices disassembled with a ruler to show the size of it.
When you turn the crank it turns a circular grinding stone. I am sure this is some tool used for sharpening something but I cannot think of what. The slots on the sides are different sizes and shapes with a locking screw to hold the items in place.