The common shape for hot chisels for use under the steam hammer is given in Fig. 156. The handle and blade are sometimes made from one piece of tool steel. Sometimes the blade is made of tool steel and an iron handle welded on as shown in the sketch. The handle next to the blade should be flattened out to form sort of a spring which permits a little give when using the chisel. The edge of the chisel should be left square across and not rounding. The proper shape is shown at A, Fig. 157, Sometimes for special work the edge may be slightly beveled as at B or C. For cutting or nicking bars cold, a chisel similar in shape to Fig. 158 is sometimes used. This is made very flat and stumpy to resist the crushing effect of heavy blows. For cutting into corners a chisel similar in shape to Fig. 159 is sometimes used. For bent or irregular work the chisel may be formed accordingly. For cutting off hot stock the method used is about as illustrated in Fig. 160, i.e., the work is cut nearly through as shown at A. The bar is then turned over and a thin strip of steel with square corners placed on top as shown at B. A quick heavy blow of the hammer drives this steel bar through the work and carries away the thin fin shown, leaving both of the cut ends clean and smooth.
Fig. 156. Steam Hammer Chisels.
Fig. 157. Sections of Chisel Blades.
Fig. 153. Chisel for Cutting Cold Bars.
Fig. 159. Chisel for Cutting Into Corners.
Fig. 160. Method of Cutting Off Hot Stock.