The hack, if held perpendicularly, will not cut the end of either piece square. If one end is to be cut square, the cutter should be held as shown at c. Round material may be cut similarly, but to avoid marring its circular section it may be held in a swage fitted to the hammer die.
Flat stock may be cut equally from both sides, or if it is cut nearly through from one side, the operation can be completed by placing a small piece of square untempered steel over the cut, as shown at e. A sharp blow of the hammer will drive the steel through into the opening and produce a straight, smooth cut.
When a semicircular end is to be produced, similar to that indicated by the broken line at d, the circular cutter should be used. Here, also, the cutting should be done equally from each side.
Fig. 108.—The Checking Tool or Side Fuller.
121. The checking tool or side fuller ([Fig. 108]) is made of tool steel with a carbon content, the same as for the cutters. The handle also is the same, with the exception of part a, which provides the spring. Here, on account of its being used in two different positions, a twisted form is much better, because the tool may spring in either direction. From the end view you will notice that it has a triangular section with one square corner and two curved ones.
A convenient dimension for this tool is about 21⁄2 inches over all from the square to the circular corners. It would be convenient to have a smaller one also, of about 11⁄2 inches. The length of this tool should correspond with that of the cutters.
In use, one of the circular corners of the checking tool is forced into the metal, forming a triangular-shaped depression, as shown at b. Two depressions are shown in this sketch in opposite directions to each other, made by holding the tool in different positions and using both the circular edges. The object of this operation is to set off the rectangular portion b so that the ends c-c can be drawn out without disturbing the center.
Fig. 109.—The Fuller.