KEYS. Machine-made Keys.—Fig. 1 represents the shape of machine keys made by the Sandwich Manufacturing Co., of Sandwich, Ill., in the following manner : Each machine con sists of three co-acting, revolv ing steel hammers, the upper and principal set acting on and drawing out the heated rod to its required taper, and the side-sets acting on the edge and forging the sides to true lines. Adjustable gauges regu late the length and taper, self acting shears with gauge cut off the forged end of the rod to the exact length required, after the quick thrust to the forging roll ers or hammers, and self-acting straightening jaws seize and straighten each key as it drops from the shears, and then drop it into a cooling-hopper. In the operation of forging, each operator has six or eight bars or rods of the required size for the job in hand, in his slow fire. Drawing one from the fire and turning to his machine he thrusts it between the hammers against the gauge, which determines the length of the key, and in the moment while retiring it the action of the hammers forges it perfectly to the required taper and form. It is then pre sented to the shears, and the formed key is cut from the rod. He usually forges and cuts about three keys and returns it to the fire for a new heat, takes a fresh rod and repeats the operation, and so on through the six or eight, by which time the first one returned is suffi ciently heated. The usual sizes, made for stock. are I, and in. wide, by from n to in.
thick and from 2i- to 4 in. long.
The Woodruff System of Keying.—The Woodruff Manufacturing Co., of Hartford. Conn., has brought out a novel system of keying, which is illustrated in the accompanying cuts.
Under this system the key-seat is cut longitainally in the shaft, as shown in Fig. 2. by means of a milling-cutter (Pig. 3). This cutter corresponds in thickness to the key to be inserted, and is of a diameter corresponding to the length of the key. The key being a semicircle, the cutter (Fig. 3) is sunk into the shaft as far as will allow sufficient projection of the key above its surface to engage the key way in the hub it is designed to hold in position. The operation of cutting the key-seat is simple, and does not require skilled labor. Where a long key or feather is required, two or more keys are in serted, in the man ner shown in Fig. 2. Owing to its peculiar shape, the key may be slight ly inclined, so that it will serve to sup port the pulley on a vertical shaft, provided the key-seat in the hub of the pulley is made tapering and of the proper depth. There are twenty-five different sizes of keys used in the system, the standard scale of sizes being such as to meet the requirements of a large Majority of the machines now made.
The accompanying table gives the size and strength of these standard sizes.
Key-Seat MilHim-Machine: see Milling-Machines.