A rod of this class is shown by Fig. 40. When such rods are to be short, the forging is accomplished with two pieces, which are welded together at the conclusion of the forging, the joint being in the middle of the rod.

The fork-piece or boss-piece may be forged either solid or with a gap. If forged solid, the gap or opening may be afterwards formed by drilling and slotting. To forge a solid fork-piece for a small rod, the smith commences by selecting or making a bar whose width and thickness are about twice that of the intended piece. The work is welded and reduced by a steam-hummer to the outer forged dimensions of the boss. After which, top and bottom fullers are driven into the work at the inner extremity of the boss, which is denoted in the Figure by C. The fullers reduce the metal in order to produce the inner curves by which the boss-piece is terminated and the intermediate part of the rod commenced. After two hollows or concave recesses which are parallel to each other are thus formed by the fullers, the work is placed at right angles to its former position, and two new hollows are formed. By such reducing with fullers, the fibres are curved and arranged into a graceful position and relation to the boss, and to the intermediate part of the rod; and the required shape of the boss-piece is obtained. The outer extremity of the work is then curved by a half-round top-tool, or by holding the work with the hot end in a half-round bottom-tool, and upsetting by sledge-hammering the upper cold end. When the boss is tolerably-shaped by fullers, top-tools, or upsetting, the boss-stem is reduced to its proper diameter, and increased to its desired length to become the intermediate part of the rod.

For making the screw-end of the rod but little forging is needed, if the iron which is selected were properly prepared by rolling ; if not, it is thoroughly welded and steam-hammered, for two reasons - to obtain a tenacious iron in which the lengths of the fibres are parallel to the length of the rod, and to obtain sufficient solidity in that part which is to be formed into the screw.

When rendered sufficiently hard and close by hammering, the two pieces are united by a tongue-joint, or by a scarf-joint, if the rod is not more than 11/2 inches in diameter.

Small connecting-rods of this class are sometimes used for imparting motion to the slide-valves of land-engines, and are attached to slide-rods similar to Fig. 47.