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44. The Hammer Blows.—Metal can be forced into desired shapes or forms by delivering the hammer blows in different ways. All hammer blows are not alike; some will have one effect and others will produce an entirely different result.

45. The upright blow is delivered so that the hammer strikes the metal in an upright position and fully on the anvil. Such blows force the metal equally in all directions, providing the surrounding dimensions are equal. They will also reduce the thickness of the metal in the direction in which they are delivered, the reduction depending upon the amount of force put into the blows. They are used for drawing where the metal is supposed to spread equally in all directions and for making smooth surfaces.

Fig. 22.—The Upright Blow.

Figure 22 shows an upright blow as delivered on a piece of flat material. If the material is as wide as the face of the hammer, or wider, the force of the blow will spread the metal equally, but if it is narrower, the blow will lengthen the material more rapidly, because the hammer will cover more in length than in width.

46. The edge-to-edge blow is delivered so that the edge or side of the hammer face will be directly above the edge or side of the anvil. When blows are delivered in this manner (a, Fig. 23), the hammer forms a depression on the upper side of the metal and the anvil forms one on the bottom.