n.
Tool for pounding or delivering repeated blows.
Hand hammers have a handle and striking head. Surfaces of hammerheads vary in size, angle of orientation to the handle (parallel or inclined), and type of face (flat or convex). Carpenters' hammers often have a claw on the head for extracting nails . Weights range from a few ounces or grams up to 15 lbs (7 kg) for hammers used in breaking stones. Steam hammers often use, in addition to gravity, a downward thrust from a steam-activated piston. Pneumatic (air-driven) hammers include the hammer drill, for rock and concrete, and the riveting hammer, for construction operations involving steel girders and plate.