Hand Tools Study Guide for McGraw-Hill's Firefighter Exams (page 2)
A nail hammer is among the most widely used hand tools. It is used for striking and removing nails. Hammers are made in two general patterns: straight claw (ripping) and curved claw. Handles are made of wood, steel, or fiberglass. A hammer blow should always be struck squarely with the striking face of the hammer parallel to the object being struck. When striking another tool (chisel, wedge, hand punch, etc.), the hammer's striking face should have a diameter larger than the struck face of the other tool.
In addition to the basic straight and curved claw hammers, there are hammers designed for specialized purposes, such as light-duty tack hammers designed for driving small nails; round ball-shaped ball-peen hammers for riveting and shaping unhardened metal; soft-face hammers, or mallets, made from wood or rubber and designed for delivering blows to objects that would mar if struck with a metal hammer, and drywall hammers designed to dimple drywall prior to nailing.
Nails are made from wire. They range in length from 2 d (1 inch) to 60 d (6 inches). The abbreviation "d" is used for the term "penny" and is derived from the first letter of the Roman coin denarius. The common 16 d penny nail is 3 1/2 inches long and is used to fasten structural building elements together. Other types of nails include concrete, drywall, finishing, ring, roofing, shingle, and spiral.
Various types of chisels are used for cutting, shaping, and trimming different materials. A cold chisel made from steel is used for cutting and shaping metals such as cast iron, bronze, and copper. A wood chisel is designed for rough work on wooden materials. A masonry chisel is used with a hand drilling hammer to score or trim brick or block.
Pliers are hand tools used to grip, turn, pull, or crimp a large variety of objects. Pliers direct the power of the handgrip into a precision grip. The long handles in relation to the nose of the pliers act as levers, enhancing the force in the hand's grip to the object being acted upon.
The variety of pliers today exceeds most, if not all, other types of hand tools. Linesman pliers with a side cutting feature bend lightweight metal and sever wire. Wire stripping (electrician) pliers sever and remove insulation on electrical wire without damaging the wire. Long (needle)-nose pliers are used to grip and shape lightweight metal; the slim head design facilitates crimping wires in confined, narrow spaces. Lockjaw (vise grip) pliers are basically a handheld vise that allow for the purchase on an object to be locked in and tightened prior to applying force. They are used to firmly grip lightweight metal or remove round key-lock door cylinders.
Wrenches are used for tightening and loosening nuts, bolts, pipes, and many other objects that are hard to turn. The tool works as a lever. The mouth of the wrench is used for gripping the object to be turned. The wrench is pulled at a right angle to the axes of the lever action and the turned object. Wrenches can be nonadjustable or adjustable to fit better around objects of various sizes that need turning. An open-end wrench is a one-piece wrench with a smooth, U-shaped opening(s). It is designed to grip two opposite faces of a bolt or nut from the side. This is advantageous in areas that are difficult to access or are obstructed.
A box-end wrench is a one-piece wrench with recessed, grooved, enclosed opening(s). It is often designed double-ended with different-sized box ends. The enclosed opening grips all the faces of the bolt or nut providing more torque than the open-end wrench without slipping or stripping the bolt or nut. A combination wrench is a double-ended tool with one end open and the other end enclosed. Both ends generally fit the same size bolt or nut.
An offset wrench is designed to provide access to obstructed bolts and nuts in recessed areas. It allows for hand clearance when turning an object flush with a work surface. An adjustable-end (crescent) wrench is an open-ended wrench with smooth, adjustable jaws used to turn bolts or nuts. A pipe, or Stillson, wrench is an adjustable wrench having serrated jaws for gripping soft iron pipe and pipe fittings. A hex key (Allen) wrench is an L-shaped, six-sided wrench used to turn machined setscrews or bolt heads designed with a hexagonal recess. And, finally, the well-known monkey wrench (named for its inventor, Charles Moncky—I kid you not!) is an old-type adjustable wrench with smooth jaws that is used for turning bolts or nuts.
A ratchet box, designed for turning bolts or nuts, has a mechanism that eliminates the need to readjust the wrench during the return stroke. A socket with ratchet handle is a hollow cylinder (socket) that fits over a bolt or nut head, used in conjunction with a drive tool (ratchet handle). Sockets are generally sold in sets of various sizes.
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