Hammers. Fig. 127 shows a carpenter's hammer. The head A is wholly of steel. The face B is hardened so as not to be injured by repeated blows upon the nail, which is comparatively soft, but the idea prevailing among inexperienced workmen, that the hammer is indestructible, is a false one. When two bodies are brought together forcibly, as a hammer and a nail, the softer body yields, and a change takes place in its form. If the nail were harder than the hammer, it would not be injured, but the hammer would show an impression of the nail head. Careless or ignorant workmen sometimes take an old file for a punch or a nail-set, and use a hammer upon it. The file is harder than the hammer, and the result is that the face of the latter is badly scarred.

Fig. 125

Fig. 126

Fig. 127

The claw C makes the hammer a very effective tool for withdrawing nails.

Hammers vary in size from seven to twenty ounces; the bench-worker usually employs one weighing from fourteen to sixteen ounces.

101. The Hatchet is a useful tool for bringing large pieces of material to size roughly, and in skillful hands it may be used with accuracy as well as effect. When it is compared with the hammer, it will be seen that a blade C, Fig. 128, takes the place of the claw C, Fig. 127. As an instrument for driving nails it is clumsy, and the opening d, for withdrawing nails, amounts to but little. In sharpening, the hatchet is ground on both sides of the blade, and whetted on an oilstone.

Fig. 128