A slotted bottom tool having a half-round gap is very convenient for supporting a bolt or pin, or other cylindrical piece, while being punched or drifted. The tool may be of sufficient length to extend beyond the anvil-edge, to allow the end of the drift to clear the anvil while in the slot or key-way. In other cases a shorter bottom tool may be used, having the slot directly above the anvil-face; in either case the slot in the tool is formed entirely through it, to allow the punched pieces to be easily cleared away.

When such tools are made of cast iron or cast steel, the slots can be formed at the time of casting, and are afterwards finished with filing. If the tool should be made of wrought iron or wrought steel, the slot may be punched, or, if too small for punching, it may be drilled and afterwards finished with filing. A slotted bottom tool is indicated by Fig. 211.