119. The trimming chisel ([Fig. 104]) is made quite similar to an ordinary hot cutter and likewise provided with a wooden handle. It should be strongly constructed, perfectly straight on one side, and not too long from the cutting edge to the top to avoid its being turned over when the blows are delivered upon it. The grinding should be done on the tapered side only, with the cutting edge tempered to a dark blue.
120. The cold cutter ([Fig. 105]) is used for purposes similar to those of the ordinary cold cutter. It should be strongly made in a triangular form, as shown in the end view, also with a spring handle like that of the hack. The top is made convex, and the sides taper to the cutting edge, which should be ground equally from both sides. It should be carefully tempered for cutting cold material.
Fig. 105.—The Cold Cutter.
Fig. 106.—Breaking Cold Stock.
In cutting stock with this tool, the material should be nicked sufficiently deep on the exterior to allow it to be broken. By holding the piece securely with the hammer, and the nicked portion even with the edge of the dies, it may be broken off by a few blows from a sledge. The steam hammer may also be used to break the stock when nicked with the cold cutter. The piece should be placed on the lower die of the hammer, as shown in [Fig. 106], and broken by one or two sharp blows from the hammer. A piece of round stock can be used instead of the triangular piece of steel, with the same result. When material is being broken in this way, see that no one is standing in a direct line with the stock, as there is some liability of one or both pieces flying in either direction.
Fig. 107.—Cutting Stock.
When using the hack ([Fig. 102]) for cutting square stock, cut equally from all sides, as shown at a, [Fig. 107]. This will produce smoother ends than if it were cut unequally and will prevent the short end from turning upward when the final blows are delivered. The fin or core that is formed by the hack, shown at b, generally adheres to one of the pieces, but it can be removed by using the trimming chisel in the manner shown. These fins are commonly removed by the use of an ordinary hot cutter and sledge.