GENERAL-PURPOSE COMMON HANDTOOLS The use of common hand tools calls also for the use of some common sense. 1. Basic safety awareness concerning the potential of hand injuries 2. Use of eye protection when required 3. Proper care, cleaning, and storage will preserve for many years one of your more expensive career investments Hammers and mallets: 1. Always choose the hammer appropriate for the job to avoid damaging the work or the hammer itself 2. The hammer is amongst the most misused and abused of all the common hand tools. Much damage is done by novice mechanics that, in their frustration and inexperience "get a bigger hammer" and smash down on relatively fragile parts 3. Make sure the handle is tight before using any hammer 4. Swing hammer by bending elbow, not wrist 5. Do not choke the hammer around its neck, hold it by the handle Types of hammers and mallets 1. Metal head hammers are sized according to the weight of the head without the handle 2. Soft faced hammer have striking surfaces made of: wood, brass, lead, rawhide, hard rubber, or plastic 3. Mallet have heads are made from: hickory, rawhide, rubber

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GENERAL-PURPOSE COMMON HANDTOOLS Screwdrivers: 1. used for tightening or loosening screws or screw-head bolts 2. use a screwdriver with care on the aircraft because the simple act of slipping off the head of a screw can deeply scratch the aluminum or magnesium skin, possibly resulting later in corrosion 3. a common screwdriver must fill at least 75% of the screw slot 4. never use a screwdriver for chiseling or prying 5. do not use screwdrivers to check electric circuits 6. never hold a part in your hand when working on it Classified by: 1. shape a. common screwdriver- straight slot screws b. cross point screwdrivers: i. Phillips screwdriver, (blunt ended)- recessed head screws ii. reed and prince screwdriver, (pointed end)recessed head screws c. note: Phillips and the reed and prince are not interchangeable 2. type of blade a. square shank b. round shank c. offset screwdriver i. both ends are bent 90-degrees ii. used when vertical space is limited 3. blade length, some common lengths are 6, 8, and 10 inches

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GENERAL-PURPOSE COMMON HANDTOOLS Pliers A. range in size from 5 to 10 inches B. the better grades are drop-forged steel C. hands are easily injured with pliers, keep fingers away from jaws or cutting surfaces D. Don’t use pliers to turn nuts. In just a few seconds pliers can damage a nut more than years of service 1. Slip-joint pliers a) range in size from 5-10 inches b) 6-inch preferred size for aircraft repair work c) permits the jaws to be opened wider at the hinge for gripping larger objects d) used to grip flat or round stock 2. Diagonal pliers (dikes) a) short-jawed cutter with a blade set at a slight angle on each jaw b) cut wire, rivets, small screws, and cotter pins c) remove and install safety wire 3. Needle-nose pliers a) used to hold objects b) make adjustments in tight places c) come in both straight and 90-degree types 4. Duckbill pliers a) jaws are thin, flat and shaped like a duck's bill b) used for twisting safety wire 5. Flat-nose pliers a) good for making flanges b) jaws are square, fairly deep, and usually well matched 6. Water pump pliers (channel locks) a) slip-joint pliers with the jaws set at an angle to the handles 7. Vice-grip pliers a) hold small work in a portable vice b) remove broken studs c) pull cotter pins

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GENERAL-PURPOSE COMMON HANDTOOLS Punches Used to start holes for drilling, punch holes in sheet metal; remove damaged rivets, pins and bolts; And aligning parts for assembly Various types of punches: 1. Center punch a) for making large indentations in metal for starting a twist drill b) ground to a point with an angle of 60-degrees 2. Prick punch a) used for placing reference marks on metal b) also used to transfer dimensions from a paper pattern directly on the metal c) ground to a sharp point 3. Starting punch a) a special punch having a flat face and tapered shank b) used to start a rivet or fastener from its hole c) it is used until it's tapered body fills the hole, then a pin punch can be used to drive the rivet or fastener out the rest of the way d) helps prevent bending your pin punch 4. Pin punch (often called drift punches) a) has a flat face and straight shank b) sized by the diameter of the face in thirty-seconds of an inch c) sizes range from 1/16-3/8 inch in diameter 5. Transfer punch a) used to mark rivet holes using an old skin as a template for laying out new skin b) shank is straight, the same size of the rivet hole being transferred, and has a sharp point in its exact center 6. Aligning punch a) long narrow tapered shank b) used for aligning two or more parts for bolting together

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GENERAL-PURPOSE COMMON HANDTOOLS Wrenches 1. Used for tightening or removing nuts and bolts 2. one of the strongest and most widely used metals for making wrenches is chrome-vanadium steel Various types of wrenches: Open-end wrenches A. both ends are open for sliding onto the fastener B. jaws may be parallel to the handle or at an angle up to 90 degrees (most are 15 degrees) Box-end wrench A. the box (or closed end) completely surrounds the fastener B. good for working in close quarters when only a small amount of rotation of the fastener is possible at a time C. most come in 12 point design so that they will work in places having as little as 15 degrees swing Combination wrench A. has a box-end on one end, and an open-end on the other (both of the same size) B. permits breaking the fastener loose with the box end, then loosening it quickly with the open end (the box end is slower in that it must be lifted above the fastener after each swing) Socket wrench A. its over the top of the nut or bolt completely enclosing it, providing access from some distance away with the use of extensions B. can be used with a ratchet wrench to speed-up removal and installation C. also can be used with a torque wrench to apply required torques D. available in either 4, 6, or 12 sided recess to fit a nut or bolt head

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GENERAL-PURPOSE COMMON HANDTOOLS Special wrenches: Spanner wrench A. used on such components as hydraulic actuators, shock struts, and pump assemblies B. the hook spanner for round nut with a series of notches cut in the outer edge C. has a curved arm with a hook on the end which fits into one of the notches on the nut D. the hook is placed in one of these notches with the handle pointing in the direction the nut is to be turned Allen wrench A. most headless setscrews are the Allen type and must be installed and removed with an Allen wrench B. range in size from 3/64-1/2 inch C. the wrench is a "l" shaped six-sided bar Torque wrench A. many aircraft nuts and bolts require a definite pressure to be applied in the tightening process B. this pressure is called “torque” I.too little pressure in some cases can result in improper sealing, loose fit, or excessive wear II.too much torque can result in excessive stress on the bolt, nut, and part, and possible failure of the fastener or cracking of the part C. the torque wrench is a precision tool consisting of a torqueindicating handle and appropriate adapter or attachments D. it measures the amount of turning or twisting force applied to a nut, bolt, or screw

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GENERAL-PURPOSE COMMON HANDTOOLS Torque recommendations The strength of the joint provided by a threaded fastener such as a bolt and nut is determined by the proper preloading of the threads A. if too much torque is used, the excess tensile stress may cause the bolt and its threads to be damaged (elongated) or the part destroyed (crushed) B. if too little torque is used, the loads imposed on the part may put enough shear stress into the bolt to cause it to fail (the mating surfaces of the parts that the bolt is supposed to be holding may slip) C. using the proper torque allows the structure to develop its designed strength and greatly reduces the possibility of failure due to fatigue D. always torque to manufactures recommended values E. torque charts and specifications are always based on clean and dry threads, unless otherwise specified (using thread lube) F. use only a currently calibrated torque-wrench G. to obtain values in foot-pounds, divide inch-pounds by 12 H. always tighten by rotating the nut first if possible I.if the bolt head must be torqued instead of the nut, approach the high side of the torque range but do not exceed the maximum allowable torque II.also, the maximum amount may be increased by an amount equal to shank friction, provided the shank friction was first measured by a torque wrench I. when tightening castellated nuts on bolts, the cotter pin holes may not line up with the slots in the nut I.The nut must never over-torqued to make the hole in the bolt align with the castellation II.switch to a thinner washer and re-try

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GENERAL-PURPOSE COMMON HANDTOOLS Torque wrenches Three most commonly used torque wrenches: 1.Flexible beam Torque read visually on indicator scale 2.Rigid frame

Torque read visually on a dial type indicator

3.Ratchet type (also called the clicking torque wrench). When the applied torque reaches the torque value set into the wrench in the handle setting, the handle will automatically release or “break” and move freely a short distance Over-torque When a bolt is stretched beyond it’s... “Elastic” limit, it enters a... “Plastic” state (permanent deformation) until it “Yield” level and... “Fails”

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reaches it’s...

GENERAL-PURPOSE COMMON HANDTOOLS Torque wrench extensions Adding an extension that makes the torque wrench longer changes the amount of torque that must be applied (reduces it because of the lever action) To determine what a torque wrench should indicate when an extension is added to it use this formula: Tw = ta x l (l + a) Where: Ta= actual (desired) torque Tw= apparent (indicated) torque L= length of torque wrench A= added length of extension Example 1: 6 inch extension 100 inch-lbs. required torque 8" torque wrench Tw = 100 x 8 = 800 (8+6) 14 Tw = 800 divided by 14 = 57.1 inch-lbs. Torque

Example 2: 3 inch extension 50 inch-lbs. (required torque) 10" torque wrench Tw = 50 x 10 = 500 (10 + 3) 13 Tw = 500 divided by 13 = 38.4 inch-lbs. Torque

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GENERAL-PURPOSE COMMON HANDTOOLS Metal cutting tools Hand snips Used for cutting light sheet metal. Snips should never be used to cut heavy sheet metal Various types of hand snips: 1. Straight snips. Used for cutting straight lines when the distance is not great enough to use a squaring shear and for cutting the outside of a curve 2. Curved snips. Used for cutting the inside of curves or radii 3. Hawksbill. Used for cutting the inside of sharp curves or radii 4. Aviation snips I. designed for cutting heat-treated aluminum alloy and stainless steel II. blades have small teeth on the cutting edges and are shaped for cutting very small circles and irregular outlines III. available in two types, those that cut from right to left and those that cut from left to right

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GENERAL-PURPOSE COMMON HANDTOOLS Metal cutting tools (continued) Hacksaws I. consists of a blade, frame, and a handle II. blades are made of high-grade tool steel or tungsten steel and are available in sizes from 6 to 16 inches in length III. the 10 inch blade is most commonly used IV. blade is always mounted with the teeth pointing forward, away from the handle V. two types of blades are available, the all-hard blade and the flexible blade a. the flexible blade has only the teeth hardened and is best for sawing hollow shapes and metals having a thin cross section b. an all-hard blade is best for sawing brass, tool steel, cast iron, and heavy cross-section materials VI. once the cut is started, make each stroke as long as the hacksaw frame will allow

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GENERAL-PURPOSE COMMON HANDTOOLS Metal cutting tools (continued) Chisels A hard tool steel cutting tool which can be used for cutting and chipping any metal softer than the chisel itself. Always use a ball-peen hammer when using a chisel Various types of chisels: 1. Flat cold chisel a. b. c. d. e.

most common type of chisel used in aircraft maintenance used to cut wire, strap iron, or small bars and rods range from 5/16-11/16 inch across 5-8 inches long cutting edge is ground to an angle of about 60-70 degrees

2. Cape chisel a. used to cut keyways and channels b. Used also to knock the head off rivets after the head has been drilled through. Their narrow cutting edge is less likely to damage the skin than the wider cold chisel c. caution must be exercised in its use as much structural damage can result from careless cutting operations of hard steel fasteners on soft aluminum skin 3. Round nose chisel a. used for cutting rounded or semicircular grooves and corners 4. Diamond point a. used for cutting grooves and inside sharp angles

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GENERAL-PURPOSE COMMON HANDTOOLS Metal cutting tools (continued) Files Used to: square ends, file rounded corners, remove burrs and slivers from metal, straighten uneven edges, file holes and slots, and smooth rough edges Various types of files: Hand files a. used principally for finishing flat surfaces b. uniform in width but taper in thickness c. has double-cut teeth Flat files a. most common files in use b. tapered toward the point in both width and thickness c. cut on their edges as well as their sides d. double-cut on both sides, single cut on edges Mill files a. used for draw filing and filing soft metals b. tapered slightly in thickness and in width for about one-third of their length c. single-cut teeth Square files a. used for filing slots and key seats, and for surface filing b. tapered or blunt, double-cut Round or rattail files a. used for filing circular openings or concave surfaces b. may be tapered or blunt, and single- or double-cut

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GENERAL-PURPOSE COMMON HANDTOOLS Metal cutting tools Files: (continued) Triangular and three-square files a. triangular files are single-cut, and used for filing the gullet between saw teeth b. three-square files are double-cut, and may be used for filing internal angles and corners Half-round files a. used where their shape permits them to work where flat files won't, like a wide inside radius b. cut on both the flat and round sides c. may be single- or double-cut Knife file a. used for filing acute angles b. tapered in thickness and in width c. have a sharp edge Wood rasp file a. used to remove wood where it is not practical to use a saw or a plane b. the surface is left quite rough and must be smoothed with a file or sandpaper c. have individual teeth cut into their surface rather than rows of teeth d. usually half-round and tapered Vixen files (body files, or curved tooth file) a. used to produce a smooth finish by slicing off very small amounts of material at a time b. often come in a special file holder which slightly arches the file for more concentrated cutting pressure c. have curved teeth

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GENERAL-PURPOSE COMMON HANDTOOLS Metal cutting tools (continued) Care of files: 1. Choose the right file for the material and work 2. Keep all files in a rack and separated so the don't bear against each other 3. Keep the files in a dry place, rust will corrode the teeth 4. Keep files clean, tap the end of the file against the bench after every few strokes, to loosen and clear the filings. Use the file card to keep files clean. A dirty file is a dull file

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GENERAL-PURPOSE COMMON HANDTOOLS Metal cutting tools (continued) Twist drills Wood bits and twist drills are a quick and inexpensive method of cutting holes in material a. they are used in conjunction with either a hand or power drill to turn them b. the drill motors may be stationary or portable, hand, electric, or pneumatic operated c. twist drills are made of carbon steel or high-speed alloy steel d. carbon steel twist drills are satisfactory for general work e. high-speed twist drills are required for harder metals such as stainless steels Twist drills come in three sets: a. number drills range in size from 0.0135 for the number 80 drill to 0.2280 for the number one drill b. fractional drills are available from 1/64 inch to 1/2 inch c. letter drills are all larger than the number drills and range from the "a" drill (0.2300) to the "z" drill (o.4130) The principal parts of a twist drill are: a. shank - fits into the drill chuck b. body - forms the core of the drill c. point I.lip angle should be 59 degrees for most cutting operations (this is an overall cutting angle of 118 degrees) II.lip clearance should be 125-135 degrees

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GENERAL-PURPOSE COMMON HANDTOOLS Metal cutting tools (continued) Reamers Used to smooth and enlarge holes to exact size 1. hand reamers have square end shanks to they can be turned with tap wrench or similar handle 2. a hole that is to reamed to exact size must be drilled to about 0.003 to 0.007 inch undersize 3. reamers are made of either carbon tool steel or high-speed steel 4. reamer blades are hardened to the point of being brittle and must be handled carefully to avoid chipping them

Countersink 1. used to cut a cone-shaped depression around a hole to allow a countersunk rivet or screw to set flush with the surface 2. installed in a standard drill motor chuck and used in a similar manner as the twist-drill a. 82° machine screws b. 100° flush head rivets and machine screws

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