Understanding and Using Different Types of Wrenches: A Comprehensive Guide, Study notes of Engineering

Download Understanding and Using Different Types of Wrenches: A Comprehensive Guide and more Study notes Engineering in PDF only on Docsity! TM 9-243 Chapter 25 WRENCHES HOW TO CHOOSE AND USE THEM The “Types and Uses” section provides you with a list of The “Using” section tells you how to use the wrench to some of the types of wrenches. These pages should perform the desired function, The “Care” procedures help you select the right wrench to do the job. tell you how to care for the items. INDEX Item Page TYPES AND USES . . . . . . . . . . . . . . . . . 25-2 Open-end wrenches . . . . . . . . . . . . . . . . 25-2 Box wrenches . . . . . . . . . . . . . . . . . . . . . . 25-3 Combination wrenches . . . . . . . . . . . . . . . 25-4 Socket wrenches . . . . . . . . . . . . . . . . . . . 25-5 Socket wrench handles, extensions and adapters . . . . . . . . . . . . . . . . . . . . . 25-6 Special purpose socket wrenches . . . . . 25-7 Crowfoot wrench . . . . . . . . . . . . . . . . . . . 25-9 Hex key wrench . . . . . . . . . . . . . . . . . . . . . 25-9 Plug wrenches . . . . . . . . . . . . . . . . . . . . . 25-9 Adjustable open-end wrench . . . . . . . . . 25-10 Clamp pliers . . . . . . . . . . . . . . . . . . . . . . . 25-10 Monkey and auto wrenches . . . . . . . . . 25-10 Pipe wrenches . . . . . . . . . . . . . . . . . . . . . 25-11 Torque wrenches . . . . . . . . . . . . . . . . . . . 25-11 Spanner wrenches . . . . . . . . . . . . . . . . . 25-12 SAFETY . . . . . . . . . . . . . . . . . . . . . . . . . . 25-13 USING . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25-14 CARE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25-18 25-1 TM 9-243 TYPES AND USES A wrench is a tool specially designed to tighten or loosen nuts, bolts, studs, and pipes. Wrenches are forged from steel alloy to prevent breakage. There are many differ- ent types of wrenches. Each type has its own use. By using the properwrench for the task to be done, you will not break the wrench, damage the equipment, or cause personal injury. The following section is intended to give you information on the different wrench types. OPEN-END WRENCHES The engineer’s double open-end wrench has different size openings on each end. This type of an arrangement permits a smaller number of wrenches to complete a set. The engineer’s double open-end wrench is also used to reach behind or below blind surfaces. All open-end wrenches have open jaws on one or both ends of the wrench. Most jaw openings are offset from the shank portion of the wrench by 15 degrees. The wrench length is determined by the size of the jaw opening. Some of the more common types of open-end wrenches and their uses are listed below. The construction wrench combines the open-end jaw with a long tapered shank providing a wrench/alignment punch combination. The construction wrench is used in the building trades and on heavy objects which require alignment before fastening. The engineer’s single open-end wrench has a long smooth shank providing the user with a better gripping surface. It is used to reach behind or below blind surfaces. 25-2 TM 9-243 TYPES AND USES - Continued SOCKET WRENCHES The socket wrench consists of a round metal sleeve with a square opening in one end for insertion of a handle, and a 6-point or 12-point wrench opening in the other. They are available in both common (short) and deep (long) lengths. The length of the socket does not deter- mine its size. Socket wrenches usually come in sets. The square or drive end may vary in size from 1/4 to 1 inch. In socket sets, the drive end determines the size; for example, a 1/4-inch drive set may contain nine sock- ets ranging in size from 3/16 inch through 1/2 inch. In 3/8-inch drive, the smallest socket would be 3/8 inch. This overlap in size allows better control by the user and prevents breakage of either the socket or the equipment from using the wrong size handle. A universal joint socket and spark plug socket are examples of specially designed sockets. The universal joint socket is used when it is necessary to reach around an object. The spark plug socket has a rubber insert. This insert protects the ceramic insulator when remov- ing and/or installing the spark plug. All sockets must be used with some type of handle. Sockets are used to remove and/or install common-size nuts or bolts. 2 5 - 5 TM 9-243 TYPES AND USES - Continued SOCKET WRENCH HANDLES, EXTENSIONS AND ADAPTERS Ratchet handles may have either a straight-head or a flex-head. Both types have a selection lever on the top of the head to determine the direction of drive. The flex- head is used to go around objects. Both types are used with socket wrenches for rapid removal of nuts or bolts. The sliding T-Bar handle has a single head which may be adjusted along a bar handle. It has two spring-loaded balls, one for keeping the bar in the head and the other for keeping the socket on the head. The sliding T-Bar is used for increased leverage or for working around other objects. The speed handle has a brace-type shaft with a revolv- ing grip on the top. It is used for rapid removal and/or installation of nuts or bolts, which are out in the open and have little or no torque. A hinged handle has a hinged adapter on one end which may be rotated in 90 degree steps. The hinged handle is used when additional leverage or torque is needed to loosen nuts or bolts. 25-6 TM 9-243 TYPES AND USES - Continued SOCKET WRENCH HANDLES, EXTENSIONS AND ADAPTERS (Cont) The spin-type screwdriver grip handle has a plastic or wood handle. It is used to remove and/or install small nuts and bolts. The socket wrench adapter is used to change the drive size between the socket and the handle. It usually increases or decreases the fractional size by one (1/4 inch to 3/8 inch). The socket wrench adapter is used to increase or decrease the drive end of a particular handle allowing it to be used with two different socket sets. Extensions are either rigid or flexible. They range from 2 to 17 inches in length. Extensions may be used with any socket handle combination to gain clearance above nut or bolt. The ratcheting adapter converts a non-ratcheting handle into a ratchet drive. It is used for quick removal of nuts or bolts. SPECIAL PURPOSE SOCKET WRENCHES The four-way socket wrench has four nonremovable sockets attached to four arms. Each of the sockets is a different size. The four-way socket wrench is usually used to remove or install the wheel stud nuts of a vehi- cle. The handle construction provides extra leverage when loosening and tightening the stud nuts. 25-7 TM 9-243 TYPES AND USES - Continued ADJUSTABLE OPEN-END WRENCH MONKEY AND AUTO WRENCHES The adjustable open-end wrench has one fixed jaw and a movable or adjustable jaw. The adjustable jaw is set against the face of the nut by turning a knurled worm gear. Care must be exercised when using an adjustable wrench. Always use the fixed jaw for applying pressure to tighten or loosen nuts or bolts. Adjustable wrenches are used to remove and/or install nuts, bolts, and studs when the correct size wrench or socket is not available. CLAMP PLIERS The clamp pliers are generally used more as a wrench than as a pair of pliers. It has a fixed jaw and handle which contains an adjustment screw for the movable jaw. The other handle is in two sections, one section to apply pressure and to lock the pliers, and the other section, when pulled, to release the grip. Clamp pliers are used to hold or clamp nuts and bolts which have been rounded off by using the wrong size wrench. The monkey and auto wrenches are similar and have one fixed jaw and an adjustable jaw which moves along the handle by turning a knurled worm gear. Monkey and auto wrenches are used to install or remove odd size nuts and bolts. An adjustable wrench must be used with care. Always apply pressure against the fixed jaw. 25-10 TM 9-243 TYPES AND USES - Continued PIPE WRENCHES There are three basic types of pipe wrenches, the stillson wrench, the strap wrench, and the chain wrench. They are all used to connect or break pipe joints or to turn cylindrical parts. The stillson pipe wrench has a fixed jaw which is on the end of the handle and an adjustable jaw at the top of the wrench. Adjustment is made by turning a knurled adjusting screw which moves the jaw. Always pull the pipe fitting towards the fixed jaw. The serrated (grooved) jaws of the stillson wrench will mar soft pipe. Strap pipe wrenches have a leather or canvas strap which is attached to the handle. The strap is looped around the pipe and back through the handle to grip the pipe. The strap pipe wrench will not scratch the surface of the pipe. Chain pipe wrenches have a section of bicycle-type chain permanently attached to the handle. The upper section of the head has teeth which mate with the links of the chain. The chain is wrapped around the pipe and pulled over the head section of the wrench to grip the pipe. Chain pipe wrenches will scratch the surface of the pipe. T O R Q U E W R E N C H E S Torque wrenches are designed to measure the spe- cific degree of tightness of nuts or bolts. Torque wrenches are considered precision instruments and therefore must be calibrated at regular intervals. Torque wrenches are used for final tightening of nuts or bolts. Torque wrenches are normally calibrated in a right-hand direction only. If a unit is required to perform torquing operations in a left-hand direction, they must request that the supporting calibration fa- cility calibrate the torque wrench in both directions. A dial torque wrench has a head which contains the drive element and a dial for reading the exact amount of torque. Change 1 25-11 TM 9-243 TYPES AND USES - Continued TORQUE WRENCHES (Cont) A scale torque wrench has a rod which runs parallel to the handle and the drive element. This rod moves across the scale to the right or left as torque is applied. POWER TORQUE WRENCH Using a powerful gear train, the power torque wrench is completely mechanical in operation. The power torque wrench is operated by a hand crank. The torque is calibrated in foot pounds, which is shown by a dial indicator on the top face of the power torque wrench. This type of torque wrench is used for tightening nuts and bolts requiring 200 or more foot pounds of torque. NOTE A special feature of this type of torque wrench is that it is possible to loosen as well as tighten nuts and bolts. SPANNER WRENCHES Two basic types of spanner wrenches are the hook-type and the pin-type. Hook-type spanner wrenches are either fixed or adjustable and are normally used to tighten fire hoses or similar couplings which have a protruding lip. Pin-type spanner wrenches have pins protruding from the handle which fit into holes in the coupling or plate to be tightened or loosened. Spanner wrenches are special purpose wrenches and are to be used only for their intended purpose. HOSE COUPLING PIN FIXED HOOK ADJUSTABLE HOOK Three kinds of hook-type wrenches include the hose coupling pin, for tightening and loosening hose coupl- ings, the fixed hook, for tightening or loosening coupl- ings with protruding rims or edges, and the adjustable hook-type. The adjustable hook-type is similar to the fixed hook- type. However, it may be adjusted around objects and fastened before use. 25-12 Change 1 TM 9-243 USING AN ADJUSTABLE OPEN-END WRENCH 1 Place the wrench (1) on the nut (2) so that the force used to turn it is applied to the stationary jaw side of the wrench. 2 Tighten the knurled adjusting nut (3) until the wrench fits the nut as tightly as possible. CAUTION If the wrench does not fit tightly, it will slip and round the corner of the nut. 3 Swing the wrench clockwise to tighten the nut. 4 After the nut is tight, set it up (final tightening). USING AN ADJUSTABLE STRAP PIPE WRENCH 1 Loop the strap (1) around the pipe (2) in the oppo- site direction to that in which the pipe is to be rotated. 2 Slip the end of the strap through the shackle (3) and draw it up tightly. 3 Pull the handle (4) to turn the pipe in the desired direction until the desired tightness is obtained. NOTE The jaw (5) at the end of the shackle will seat against the strap and, as the handle is pulled, the strap will tighten and turn the pipe. 25-15 TM 9-243 USING THE TORQUE WRENCH 1 Select proper size socket wrench (1) and attach to torque wrench square drive (2). 2 Place socket wrench on work and pull the torque wrench handle in the desired direction to tighten the work. NOTE The tightening torque will be indicated on the dial or scale (3), depending on the type of the torque wrench used. 3 Remove the wrench when the torque on the dial or scale is reached. USING THE POWER TORQUE WRENCH NOTE The following procedure is not the only application for the power torque wrench. However, use of this tool is basically the same regardless of model or application. 1 To tighten a nut, set the knurled ratchet indexer (1) (located on the front of the wrench) in the same direction the handle will be turned. 2 Install applicable socket (2) onto the nut to be tightened. 3 Install square drive bar (3) into the socket. 25-16 TM 9-243 USING THE POWER TORQUE WRENCH - Continued CAUTION Different reaction adapters are required for various operations. Be careful to use the correct reaction torque adapter. Fail- ure to do so will render torque wrench useless and can damage the equipment. 4 Install reaction torque adapter (4) over drive bar and socket as shown. NOTE When installing power torque wrench, make sure the two locking pins (5) under- neath the wrench are firmly engaged to the reaction torque adapter. 5 Install power wrench (6) onto square drive bar and reaction torque adapter. Rotate power wrench until the reaction torque adapter engages a fixed point. CAUTION Do not use impact wrench of any kind to operate this wrench. 6 Install the crank handle (7) into the square input (8) and turn in the same direction as the output must turn. 7 Continue to turn crank until torque indicator (9) shows the desired torque reading. 25-17