The striking tools comprise the various forms of hammers and mallets.
Hammers.— Ordinarily, a hammer consists of two parts — the iron or steel hammer-head, and the shaft or handle of wood which is driven into a hole in the "centre of mass" of the hammer-head. The angles at which the handles are attached to the heads vary greatly on account of the variations in the position of the centre of gravity of the head relatively to the line of the penetration of the handle, and also on account of the various convexities of the faces of the hammer-head. The form of the "pane" or the narrower or smaller end of the hammer-head also varies greatly in the hammers used for different purposes. When of hemispherical form as in the engineers' ham mers, it is called a "ball" pane; when it is made in the form of a narrow, round-edged ridge placed at right angles to the axis of the handle it is called a "cross" pane; and when the ridge runs longitudinally it is called a "straight" pane. In the claw-hammer the pane is curved upwards toward the handle and is divided by a V-shaped groove, and the head is usually attached to the handle by means of side flanges. It is very use ful for drawing nails. The hand hammers used' by wood-workers range in weight from one-half ounce to 10 pounds. The weight of the head and the balance of the head in the handle are the most important considerations controlling the suitability of a particular hammer, for if the handle is too light for the head it will break off.
Mallets.— These are forms of hammers in which the metal heads are replaced by wooden blocks. They are practically heavy wooden hammers which are used for delivering blows on the handles of chisels and gouges in order to avoid the risk of smashing and splitting them down as is usually the result when iron hammers are used for that purpose. Round faced wooden mallets are used by molders for rapping patterns in order to detach the sand which adheres to them when they are drawn from the molds. Woodworkers' mallets are
either square or round in form. The square mallets are about six inches in length and two by wood-workers range in weight from one-half inches in width. The round mallets are about five inches in length and three inches in diameter. The mallet-heads are usually made of hickory wood, and sometimes of lignum vita.
The chopping tools are the axes, the hatch ets and the adzes. In each case they represent the combination of a striking tool and a cutting tool. In these tools the shape of the handle or helve and the manner in which it is attached to the blade is of the utmost importance in gov erning their effectiveness. ' Axes and Hatchets are edged tools with handles used in chopping for rough cutting or splitting. They vary mainly as to the weight of the blade, to the shape or curvature of the handle and to the form of the cutting-edge. Axe blades range in weight from two to seven pounds. These blades are usually made by welding the hard tempered steel portion which forms the cutting-edge to the iron portion which contains the "eye° provided for the re ception of the handle. The curved form of the handle is designed to counteract the influence of the force of gravity which tends to twist the blade downwards when the axe is used for chopping at various obliquities. The form of the cutting-edge, curved horizontally, and wedge-shaped transversely to the sides of the blade, is designed for the purpose of separating the groups of wood fibres successively, and for equalizing the pressure of the blow on each side of the blade. A hatchet is a light form of axe, with usually a nail-pulling groove back of the blade.
In the adze, the cutting edge stands trans versely or at right angles to the handle, which is quite short. The entire outer face of the blade is made slightly curved, and its cutting edge is formed by beveling from the inner face. It is usually employed for the forming of lengths of wood into curved shapes.