Hand Tools Study Guide for McGraw-Hill's Firefighter Exams

Wrenches

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.

Screwdrivers

The simple handheld screwdriver is designed to tighten or loosen and remove screws. It consists of a tip or head at the end of an axial shaft that is encased inside a cylindrical handle. The handle allows the shaft to be rotated, thereby applying torque at the tip. Screwdrivers are made in a wide variety of sizes to match different screw sizes. Screwdriver heads come in many types, the most common of which are mentioned below.

A slot-head screwdriver is a flat-bladed screwdriver that fits a single slot screw. A Phillips head screwdriver is a cross-headed screwdriver with rounded corners. It is designed to slip off the screw when under high torque to prevent over-tightening. A hex head (Allen) screwdriver has a six-sided head and is used as an alternative tool to the hex key wrench.

An offset screwdriver is used to access hard-to-reach and obstructed screws where a straight shaft screwdriver is inappropriate. A ratchet screwdriver is designed for high-speed turning using a ratchet handle.

Saws

The key component of the saw is a blade with a cutting edge. Other components include the heel, the end closest to the handle; the toe, the end farthest from the handle; and the front, or bottom edge; and back, or top edge.

There are many different types of saws, designed for specific uses. The most common saws are mentioned below.

A crosscut saw is designed for making cuts in lumber perpendicular (at a right angle) to the grain. The cutting edge of the blade is beveled, allowing the blade to act like a knife edge and slice through the wood. A ripsaw is designed for cutting lumber parallel to the grain. The saw teeth are substantially steeper than those in a crosscut saw and have flat front edges that act as chisels. Both of these saws (like most Western saws) cut as they are pushed through the wood; unlike Japanese-type saws that cut on the pull stroke.

A backsaw is a thin-bladed saw having a reinforced steel or brass back that is thicker than the blade itself and limits the depth of the cut. The teeth of the blade are closely spaced. A miter saw is a back or metal-framed saw with replaceable blades. It is designed to make crosscuts and used with a miter box to make precise angle cuts.

A hacksaw is a fine-toothed saw with the blade under tension inside a frame. It is designed to cut metal. Finally, a coping (jigsaw) is designed to cut intricate shapes in wood. It has a thin blade tensioned inside a metal frame.

Bars

Bars are made of metal and come in a variety of shapes and sizes. They are generally used as first- and second-class levers for general demolition purposes (tearing out walls, removing moldings, prying apart objects, and removing nails), but are also used for chiseling, scraping, opening up wooden boxes or crates, and lifting.

A crowbar (wrecking bar) is a long-handled, relatively heavy metal tool with one curved end (claw) for prying and removing nails and one flattened end.

A pry bar is a long-handled metal tool, generally smaller and lighter than the crowbar. It has one flattened end and one tapered, pointed end and is used for prying, lifting, and removing nails. A combination pry bar and chisel tool, an offset rip bar, is similar in appearance to the crowbar. It has a small claw end and wide chisel end in an offset pattern for difficult-to-reach objects. A utility pry bar, a small, lightweight metal tool having beveled cutting edges at both ends, is designed for pulling nails, prying light objects, and scraping. A cat's paw is a small-handle pry bar with one flattened end and one rounded, curved end for prying and removing nails.

A nail puller is a metal bar designed to easily slide under the head or into the shank of an embedded nail for easy removal. The other end is a striking head for a hammer.

Other Common Hand Tools

Other common hand tools include hand punches designed to mark metal and other surfaces softer than the punch itself and to align holes and drive or remove pins and rivets; drift pins used for aligning holes in metal; and star drills used, along with a hand drilling hammer, to drill holes in masonry.