Fig. 456.
[Fig. 456] represents a key wrench which is suitable for nuts of very large size. The sliding jaw j is held by the key or wedge s, which is operated by hammer blows. The projection at r is necessary to give sufficient bearing to the sliding jaw.
Fig. 457.
For use in confined places where but little handle-motion is obtainable, the ratchet wrench is employed, consisting of a lever affording journal bearing to a socket that fits the head of the bolt. The socket is provided with a ratchet or toothed wheel in which a catch or pawl engages. [Fig. 457] represents the Lowell Wrench Company’s ratchet wrench in which a lag screw socket is shown affixed. The socket is removable so that various sizes and shapes may be used with the same wrench. Each socket takes two sizes of square and one of hexagon heads or nuts. So long as the screw runs easily, it can be turned by the wooden handle more conveniently and faster than by the fingers, and independently of the ratchet motion. When this can no longer be done with ease, the twelve-inch handle is brought into use to turn the screw home.
