This looks sorta like a saw set, for circular saw. First lift the arm with the hammer, rock back the lever, then when the lever with wooden handle is pulled down it lifts and drops the arm with the hammer, spring pressure pulling it down with some force. A saw blade could be mounted and rotated on the spindle to the right? The wing nut on the front allows the rod to slide to the right, allowing any size of circular saw to go under the hammer. This is a good one, ruggedly made for what purpose?