To avoid drilling and a part of the slotting, crank-gaps should be formed while on the anvil. For this purpose three lines may be marked upon the solid crank part to indicate the place of the gap when forged; and a chisel or small fuller is driven in at the marks to a sufficient depth to allow the indents to be plainly seen when the work is heated. The crank is next heated to about a yellow heat, and two cuts are made into the work at the two marks that are parallel to the length of the levers. These cuts are conveniently made by driving a chisel to an equal distance from both sides, but only a few inches into the place of the gap from the entrance of it. After two short cuts are thus made, a gouge chisel, whose cutting end is the width of the gap, is driven from both sides, and a portion of the superfluous gap-piece is cut out. The straight chisel is afterwards again driven in, to extend the side cuts, and the gouge again employed to deepen the gap.