Unit 2 Craft Hand Tools

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UNITS IN THIS COURSE

UNIT 1 WORKSHOP SAFETY

UNIT 2 CRAFT HAND TOOLS

UNIT 3 MEASUREMENT

UNIT 4 MARKING OUT

UNIT 5 TASK #1 - WORKSHOP PRACTICAL

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TABLE OF CONTENTS

Para Page

2.0 OBJECTIVES 3

2.1 INTRODUCTION 4

2.2 CARE OF HAND TOOLS 4

2.3 GENERAL WORKSHOP BENCH 7

2.4 HOLDING & RESTRAINING TOOLS 8

2.5 CUTTING TOOLS 14

2.6 STRIKING TOOLS 40

2.7 FASTENING AND REMOVING TOOLS 42

2.8 POWER TOOLS 51

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2.0 OBJECTIVES

The trainee will be able to:

Identify various hand tools.

State the function of various hand tools.

List the general rules for tool care.

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2.1 INTRODUCTION

Although modern industry is now very advanced there is always a need for handtools. Even the most complex machine has to be serviced regularly. Hand tools arenecessary to service machinery. Some one-off jobs, such as tool making, are doneby using hand or hand powered tools. Sheetmetal working is also carried out using

hand tools, especially if there is only one or two to be made. When choosing handtools it is important to choose the correct tool for the job. This does not just meanthe correct type of tool, but also the correct size of tool. This unit covers both handtools and power hand tools

2.2 CARE OF HAND TOOLS

A trainee must learn to see the danger that exists with badly maintained andincorrectly used tools. Often older and more experienced men are a bad influence.Misusing common hand tools is often due to laziness. You must take the time andeffort to get the correct tool from the stores, and service any worn or damaged tools.

This time will be much less than that for healing an injury, and less painful. Caringfor tools and equipment will require little, if any, extra time. The time spent takingcare of your tools will be repaid by having clean, well maintained tools you can trustwhen in service. To give maximum service they must be properly maintained. Thereare many hazards caused by the incorrect use of hand tools. (See Figure 2.1 )

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Figure 2-1

The quality of a technician's work depends on his job knowledge, his skills, and histools. Technicians normally take pride in their tools. Taking care of your tools andequipment not only helps you do better work, it also makes your work safer. Caregiven to a specific tool depends on the type of tool.

The following is a list of general guide lines for the care of tools and equipment of all

type.

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Store Tools in the Proper Place

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There is a tool designed for almost every task, but some people use the wrong toolfor the job. Often they do this because they are too lazy to get the right tool. Usingthe wrong tool can cause injury to the worker, damage the equipment, or evendestroy the tool.

Keep Tools and Equipment Clean

Very little time is needed to clean your tools when you have finished the job. No onelikes dirty tools or equipment. Keeping your tools , clean shows you have pride inyour work. Dirt and grease can destroy many tools.

2.3 GENERAL WORKSHOP BENCH

The workshop bench is a large heavy bench or table. It must be large enough toallow space for the material to be worked on. It must be heavy enough to prevent

movement of the work. The top of the bench is usually made from hardwood ormetal. It has drawers for the storage of tools. It is used for filing, grinding, andfabrication work.

Often material and tools are left on the bench top. They can be a danger and ahazard. Therefore, always keep your workbench clean and tidy. Only the tools andmaterials you are using should be on the bench.

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To restrain means to hold. For example, the seat belts in your car restrain' you frommoving if you have a crash.

Holding and restraining tools are tools that hold or position parts so that work can bedone on them. This is the first of five groups in this hand tools unit. Some tools,

however, can fall into more than one group. The Pipe Wrench is a good example, Itcan be used as a restraining, or as a fastening tool.

When we are carrying out work on a component we must make sure that it does notmove. If it does, an accident could happen. The restraints put on the work will beeither positive or frictional. (See Figure 2.2)

Figure 2-2

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TheEngineers Bench Vice

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Bench vices are bolted to the top of the workbench to hold and locate the material.The vice should be positioned between 38 to 46 inches, (1 m to 1.2m), from theground, depending on the workman's elbow height. (See Figure 2.3

Figure 2-3

Usually bench vices have a swivel base so that the work can be positioned to anyangle, and then locked in place with a lock nut. The material is held between thejaws by tightening the screw handle. The jaws are usually serrated (having smallteeth) to grip the work. Sometimes we must avoid scratching the work. Therefore,soft jaws should be used to protect the work. Soft jaws are made from a soft

material such as rubber or aluminium. (See Figure 2.4).

Figure 2-4

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The pipe vice is another common bench vice which has to be bolted to aworkbench. (See Figure 2.5).

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Combination, or slip-joint pliers, are one of the most common types of pliers, used

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Mole Grips

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2.5 CUTTING TOOLS

Cutting tools are tools that remove metal. To cut metal, the material that the tool ismade of, must be harder than the metal work piece. All cutting tools have cuttingedges. These cutting edges must have cutting angles which are usually set whenthe tool is made. The cutting angle can sometimes be replaced by the operator.

Grinding wheels are also a cutting tool, but we are not able to check the cuttingangles of the grit that cuts the metal.

Hacksaws

Hacksaw is the term given to a saw used to cut metal. It is used for cutting off, orcutting out, larger pieces of metal, before finishing work with a file. Hand saw is thename usually given to a saw that cuts wood. The hacksaw consists of an adjustableframe, a blade, a handle, and a blade tensioning screw. (See Figure 2.12).

Figure 2-12

The blade fits into the frame with the teeth pointing away from the handle. Theframe is adjusted to the blade length. A hacksaw blade is wider at the teeth than atthe back of the blade. This is done by staggering the teeth, one to the left and oneto the right. This is known as the "set" of the blade. The "set" is to prevent the bladebinding (sticking) in the slot it is cutting. (See Figure 2.13).

Figure 2-13

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Hacksaw blades are classified by the number of teeth per unit of length, e.g. 14

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teeth per inch (14 t.p.i.), or 14 teeth per 25 mm. A hacksaw blade may also beclassified by the length of the blade or by the material the blade is made of. Acoarse blade has between 14-18 teeth per unit, and a fine blade has between 20-30teeth per unit. The blade of the hacksaw is hardened only at the cutting edge. (SeeFigure 2.14).

Figure -14

A hacksaw blade is chosen to match the material it is going to cut. Normally a finetooth blade is for a hard metal,- and a coarse blade is for a soft metal. However,the blade must have more than two teeth in contact with the work at one time. (SeeFigure 2.15).

Figure 2-15

The blade should be strained slightly in the frame. After a few strokes the blade willget warm and expand. Then the tension should be adjusted accordingly. The angleof the blade to the cut should be about 30'. The sawing rate should be 40-50strokes per minute. The cutting pressure should only be applied on the forwardstroke.

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Files come in a range of shapes. The shape of the file depends on the job it has to

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Figure 2-17

The coarseness of the file's teeth w ill depend on the amount of material it has toremove. A large amount of material would need a course file. A smooth file would

only remove a small amount of rnaterial

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Files can be single cut, with the teeth cut at 45' across the file, in one direction only;or double cut, with another row 30'in the other direction. (See Figure 2.18).

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Correct Use of Files

Before filing, place the work piece firmly in the vice. If the vice jaws are knurled theycan damage the work. To protect it, use soft jaws or jaw covers. If the vice has beenset to the correct height it will allow the craftsman to swing from the shoulder withoutstooping. Precision filing can only be done by holding the body correctly. The feet

should be spread like a boxer's stance, allowing the arms to swing in line with thecut. The correct body position reduces tiring, uncontrolled file strokes, and poorvision. (See Figure 2.1 g).

Figure 2-19

During filing, hold the handle in one hand, and the end of the file with the other. Youcan 'feel' the cutting action, if you apply just enough pressure to keep the filecutting. (See Figure 2.20)

Figure 2-20

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Some metal filings, however, will not come off the file with a file card. Therefore, a

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thin strip of soft metal can be used to remove them. (See Figure 2.26).

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Figure 2-26

Files must be fitted with a handle in good condition at all times A split handle isdangerous and should be replaced. The tang of the file is very sharp and can causea serious accident. Modern file handles have a coarse internal thread, which grips

the tang when it is screwed into the handle. This will hold the handle secure. Alwaysmake sure that the handle is the correct size before you try to fit it. (See Figure2.27).

Figure 2-27

Never use a file as a lever. The hardening process makes the blade hard and brittleso it will break if used as a lever. The tang remains soft and will therefore bend inthe same situation. (See Figure 2.28).

Figure 2-28

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The cross cut chisel is often used to cut parallel grooves, or to break up a large

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area into sections. The sections can then be chipped away by a flat chisel. Thecutting edge is slightly wider than the rest of the body, which prevents the body frombinding in the groove. (See Figure 2.32)

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After the chisel has been used for awhile, the head will spread. This is called

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Off-set snips allow your hands to remain above the cut, thus permitting cuts directly

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through the centre of a large sheet. (See Figure 2.40).

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Figure 2-40

Pipe and Tubing Cutters

Metal pipe can be cut using a hand pipe cutter. The pipe cutter resembles aG-clamp with a long T handle. (See Figure 2.41).

Figure 2-41

The T-handle screws through the frame of the cutter and into the adjustable jaw. Tocut pipe correctly the cutter should be "tracked". We can track the pipe cutter bylightly engaging the cutter wheels and turning the cutter around the pipe. This willgive the cutter a "track to run on. If the cutter makes a straight track round the pipe,then we will get a straight cut. We put pressure on the cutter by turning theT-handle. Always make one complete turn with the cutter before putting on morepressure. Continue this procedure until the pipe is cut completely through.

If you apply too much pressure to the pipe cutter on the initial cut, without trackingthe cutter, it may result in a spiralling effect. This quite often happens when cuttingis done under power. The best type of cutter to use under power, is one with widerollers. The wide rollers assist the cutter to stay on a straight "track".

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When the tool is turned, a sharp wheel cuts into the tubing. Pressure is graduallyincreased until the tubing is cut. The tubing cutter is often sold in a kit that includesa cutter, a tube flaring tool, and a tube bending tool.

Hollow Punches

Hollow, or wad punches, are used for cutting holes in a variety of nonmetallicmaterials. They are most useful for cutting gasket material for flanges.

Cutting Threads

Threaded fasteners are found on almost all mechanical equipment. Two parts arerequired to make a threaded fastener, one has an external thread, such as a screw,bolt, or a threaded rod; the other has an internal thread, such as a nut, or athreaded hole. It is important that both threaded parts match each other. (SeeFigure 2.42).

Figure 2-42

A craftsman must know and understand important screw thread terminology(describing words) and dimensions. (See Figure 2,43).

Figure 2-43

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Internal Thread Cutting

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Often some object must be fastened to a metal plate with bolts or screws, but thereis no threaded hole for the bolt. In that case, a hole must be drilled then an internalthread cut with a tap. A tap is a cutting toot used to cut internal threads. Taps aremade from high quality tool steel, hardened and ground. (See Figure 2.44)

Figure 2-44

The main parts of a tap are shown in figure 2.44. The shank is the body of the tap,which is from the top of the thread cutters to the end of the tap. The lands are thethread cutters. The chamfer is the bevel at the leading end of the tap. The tap isbevelled or chamfered to make it easier to start in a drilled hole. The flutes are thegrooves between the lands. The flutes allow the metal chips to fall away from thelands. The square on the end of the shank is used to attach a tap wrench. Tapwrenches are used to turn the tap. They come in a range of sizes and shapes.(See Figure 2.45)

Figure 2-45

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The taps described above are called hand taps. In one set of hand taps there are

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three basic types. They are the plug, the second , and the taper taps. The majordifference between them is the length of the chamfer. (See Figure 2.46).

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Figure 2-46

A taper tap has a chamfer length of about 10 threads. It is used to start a tappingoperation and for tapping through holes. A through hole is one which is drilled

completely through the material.

A second tap has a chamfer length of about 5 threads. It is used after the taper taphas been used in a blind hole. A blind hole is one that is not drilled completelythrough the material.

A plug tap has a chamfer length of about one or two threads. It is used to completethe tapping of a blind hole.

It is always important that the hole is drilled to the correct size. The size of the holeis determined by the bolt that will be placed- in it. The tap and the bolt must be thesame diameter and pitch.

To calculate the hole, or drill size required, we subtract the pitch from the majordiameter. e.g. a M5 x 0.8 bolt (or tap) requires:

5 mm-0. 8 mm = 4.2 mm tapping drill.

A hole must be drilled using the correct 'tapping drill' for the thread required (asabove). A 'tapping drill' is a normal drill which is large enough to start the taper tap,but smaller than the minor diameter.

Then secure the work piece in the bench vice. Start the cut using the taper tap,making sure the tap is 90' to the planes of the work. (See Figure 2.47).

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Figure 2-47

Never use too much force. Always use cutting fluid, or you will break the tap. Clearthe tap by backing it off as often as is necessary to prevent the flutes clogging upand breaking the tap.

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External Thread Cutting.

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To thread a piece of round bar, decide which die is needed. The die should matchthe internal threads where the threaded bar it to be used. Round bar should beselected which has the same diameter as the major diameter of the die.

The bar should be chamfered on the end to be threaded, either by grinding or filing.

If we are using an adjustable round die, the die should be adjusted to the sizerequired. Tightening the adjusting screw spreads the die stock slightly. (See Figure2.48).

Figure 2-48

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loose fit. When the die is placed into the die stock, the shallow hole on the dieshould line up with the adjusting handle or set screw. This will hold the die in placewhen it is tightened. The unchamfered side of the thread cutters should go againstthe shoulder of the die stock. To start cutting, place the chamfered end of the dieonto the end of the chamfered end of the bar. (See Figure 2.49).

Figure 2-49

Lubricate the bar with cutting oil before you start the cut. Make sure the bar issecured in a vice grip, or v-clamp, to prevent the bar from turning as the threads are

cut. Press down to start the die on the bar. Make sure the thread is true to the axisof the bar. (See Figure 2.50).

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Figure 2-50

The bar must be securely supported, and vertical in the vice. When the die hasstarted to cut, turn it one-half turn forward and one quarter turn back. Repeat thisuntil the bar is threaded to the correct length. Back the die off the threads, thenclean the threads with a thread file. Always make sure the die is backed off regularlyto release the cuttings.

Cutting threads on pipe work can be done with a ratchet head pipe threader. Alonger handle is needed for pipe work to give more torque to cut the metal. Theratchet allows the handle to turn in a limited arc, which allows the technician toposition the handle where he can apply the most force.

More cutting oil is needed when cutting larger pipe.

The die has a chamfered side which is placed onto the pipe. The maximum sizepipe dies used with a ratchet head pipe threader is 50 mm.

Twist Drill

Twist drills (drill bits) are an end cutting tool used to produce holes in most typesof material. They are made from high-speed steel. A twist drill is held in a machinedrill chuck. The drill chuck is turned either by hand or by electrical power. Standarddrills have two helical grooves, or flutes, cut lengthways around the body of the drill.They provide cutting edges, allow cutting fluid to enter, and space for the cuttings toescape during drilling. A technician should know the main parts of a twist drill, howto sharpen it, and the correct speeds and feeds to use. (See Figure 2.51 ).

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Figure 2-51

Generally, drills up to 12 mm (112") in diameter have straight shanks, and thoseover this diameter have tapered shanks. Straight shank drills are held in a drillchuck. Taper shank drills are held in the internal taper of a drilling machine spindle.A tang is provided on the end of a tapered-shank drill to prevent the drill fromslipping while it is cutting. It also allows the drill to be removed from the spindleeasily and without damage.

Incorrect grinding of drill cutting angles is a common fault, causing drill failure andinaccurate drilling. If the point angle, or the cutting edges are of unequal length, thedrill will either drift or drill an oversize hole. (See Figure 2.52).

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Figure 2-52

The point angle of a drill used for general-purpose drilling is 118'. This angle can beincreased or decreased depending on the material it has to cut. (See Figure 2.53)

Figure 2-53

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2.6 STRIKING TOOLS

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Striking tools are some of the most common hand tools and probably some of themost mis used. They come in a variety of shapes and sizes, but all have specificuses. They should be used only for the job they were designed for. Misuse cancause serious injuries.

Hammers

There is a right way and a wrong way to use a hammer, regardless of the type.Always grip the hammer close to the end of the handle, this increases the leverageand power. Whenever possible, strike the object squarely with the full face of thehead to prevent damage to the hammer face, or the object. (See Figure 2.54).

Figure 2-54

The most common type of hammer is the ball-pein hammer. The main parts of theball-pein hammer are: the face (the striking surface), the pein (the round face), thewedge (used to hold the hammer head to the shaft), the eye (the hole where theshaft is located), and the shaft or handle (the wood part held during use). The flatface is for hammering, and the pein is for rounding off rivets or similar jobs.

The hammer head is held tightly on the shaft by the wedge. The eye is wider at theends so the shaft can spread and hold it more securely. If the wedge becomesloose it must be driven back in. In this hot dry country handles tend to dry out andshrink. They then become loose. Never use a hammer with a loose head, or nowedge.

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The blade of a flat screwdriver should fit the screw head exactly, neither too small or

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too big. (See Figure 2.57).

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Accidents with spanners are nearly all caused by spanners slipping from the nut.Always make sure that the spanner wrench fits the nut or bolt snugly. A spannerthat is too large will slip and take off the corners of the nut, and possibly cause aninjury to the operator. Never pack the gap between the spanner and the nut withwashers etc. This is a common misuse and is often due to the operator being too

lazy to get the correct spanner. (See Figure 2.59).

Figure 2-59

Before you apply force to a spanner make sure you are in a good steady position.Whenever possible, always pull towards the body; but do not make extra leverageby trying to extend the handles. (See Figure 2.60).

Figure 2-60

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wrench, designed for use with a hammer. (See Figure 2.61).

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Allen Wrenches

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An alien wrench is a "L" shaped piece of hexagonal tool steel. They are designedfor fastening or loosening alien set screws. A set of alien wrenches come in a rangeof metric and imperial sizes. The size is taken across the flats of the wrench. (SeeFigure 2.64).

Figure 2-64

Pipe Wrenches

Pipe wrenches are heavy duty adjustable wrenches, usually made wit high tensilestrength handles and forged jaws. They come in a range of sizes, all having thesame three main parts: the fixed jaw and handle, the adjusting nut, and the movablejaw. (See Figure 2.65).

Figure 2-65

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Special Wrenches

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Spanner wrenches are used on large bolts or nuts which have notches which thespanner wrench fits into. The most common is the hooked spanner, and the endspanner wrenches. (See Figure 2.68).

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Figure 2-68

The hooked spanner hooks onto the side of the nut as shown in figure 2-68. An endspanner hooks onto both notches on the end of the nut.

Riveting Tools

Riveting is a permanent method of fastening pieces of sheetmetal together. Theprocess consists of drilling or punching the material, inserting the rivet, then closingthe rivet by applying a compressive force. The primary types of rivets are: solidrivets, tubular rivets, split rivets, and pop rivets. (See Figure 2.69).

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Figure 2-69

Solid rivets can be made from steel, brass or aluminium, depending on their use.They may have round, flat or countersunk (W" shaped) heads. Tubular and splitrivets are used for lightweight material such as leather, although steel tubular rivetsmay be used on sheet metal.

During a pop riveting exercise the rivet is placed through the two pieces of sheetmetal. The rivet is flattened against the sheet metal to hold the two pieces together.Then the rivet is closed by squeezing the operating handle until the mandrel (specialpin through the rivet) snaps (breaks through the rivet). (See Figure 2.70).

Figure 2-70

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as sheet metal pipe work or ducting. The plier type riveting gun is useful for rivetingin confined places It is, however, unsuitable for large dimension rivets, due to itsreduced leverage capacity. (See Figure 2.71)

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The tool which actually cuts the hole is the twist drill (drill bit). Drill bits are available

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Impact Wrench

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An air powered impact wrench uses an air motor and a special clutch. The clutchchanges the rotation to a series of fast impulses (quick onoff blows). A socketwrench is attached to the square anvil at the end of the air wrench. The socket isthen placed over a hexagon bolt or nut. The impulses from the air wrench deliverfast sharp blows to the bolt head.

The motor of the impact wrench is reversible. Operating the motor in one directionwill tighten the bolt. Operating the motor in the other direction will loosen the bolt.(See Figure 2.73).

Unit 2 Craft Hand Tools

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