The primitive celt, which was hardly more than a wedge, has been differentiated into three modern hand tools, the chisel, the ax, Fig. 139, and the adze, Fig. 141.
The ax has also been differentiated into the hatchet, with a short handle, for use with one hand, while the ax-handle is long, for use with two hands. Its shape is an adaption to its manner of use. It is oval in order to be strongest in the direction of the blow a
There are two principal forms, the common ax and the two bitted ax, the latter used chiefly in lumbering. There is also a wedge-shaped ax for splitting wood. As among all tools, there is among axes a great variety for special uses.
|Fig. 139. Ax.||Fig. 140. Shingling Hatchet.||Fig. 141. Carpenter's Adze.|
The hatchet has, beside the cutting edge, a head for driving nails, and a notch for drawing them, thus combining three tools in one. The shingling hatchet, Fig. 140, is a type of this.
The adze, the carpenter's house adze, Fig. 141, is flat on the lower side, since its use is for straightening surfaces.