Caution Suitable Hammer Never drive hardened-steel cut nails or masonry nails with a nail hammer. These nails will shatter under the force of an indirect or glancing blow. Instead, use an engineer’s (sledge-type) hammer. 2.5.2 Ball Pein Hammers Ball pein hammers, Figure 2-27, are one of the most frequently used hammers. They are designed for striking chisels and punches and for riveting, shaping, and straightening metal. Ball pein hammers are available with head weights ranging from 2 oz. to 48 oz. (55 g to 1360 g), depending on the task. When striking a tool like a chisel or punch, the hammer face should be ⅜″ (9.5 mm) larger than the struck tool. 2.5.3 Soft-Faced Hammers The heads of soft-faced hammers or mallets are made of wood, rawhide, rubber, plastic, copper, or brass. See Figure 2-28. They are used where steel hammers would mar or damage the workpiece. 2.4.3 Using Screwdrivers Safely • Always fit the tool to the work. The size of the screw and the type of drive opening determine which driver to use. • Never use a driver to do the job of another tool. • Never push a driver beyond its capacity. For heavy work that requires a wrench to help do the turning, use a square-shank driver. • Never use a driver at an angle to the screw. The driver could slip and damage the screw head or cause injury. • Never expose a driver to excessive heat. • Never depend on a driver’s handle or covered blade for insulation from electricity. 2.4.4 Repair or Replace? Do not attempt to repair most types of drivers. Drivers with cracked handles, bent or twisted shafts, or worn tips should be discarded and replaced. The tip of a straight-blade driver, however, can be dressed (squared) on a bench grinder. Be careful to avoid letting the tip get hot. This will draw the temper (hardness) causing the tip to become soft and easily damaged. 2.5 Hammers Hammers are used for various striking opera- tions. It is important to use the correct hammer and to use it properly. For example, a nail hammer should not be used to strike a chisel or other hard- ened tool. Likewise, a soft-faced hammer should not be used to drive a nail nor should a sledge- type hammer be used to drive a brad. 2.5.1 Nail Hammers Nail hammers are made in two patterns: curved claw and straight claw. See Figure 2-26. They are available in various head weights for different types of nailing: 16 oz. (450 g) and 20 oz. (570 g) hammers are for general use 22 oz. (625 g) and 28 oz. (795 g) hammers are used for heavy-duty framing work. Framing hammers usually have longer handles than those for general use. Handles are made of wood, fiber- glass, or steel. A B CooperTools Goodheart-Willcox Publisher Figure 2-26. Nail hammers are available in a variety of weights and in either curved-claw or straight-claw patterns. A—Curved claw hammer. B—Straight-claw hammer. 26 Heating and Cooling Essentials Copyright Goodheart-Willcox Co., Inc.