chap09 pps Automotive technology at University of Cambridge

Figure 9–9 A typical flex handle used to rotate a socket, also called a breaker bar becauseit usually has a longer handle than a ratchet and therefore, can be used to apply more torque t

start

• Describe what tool is best to use for each job.

(trade name) and the proper name for tools

After studying Chapter 9, the reader should

be able to:

OBJECTIVES:

adjustable wrench • aviation tin snips • beam-type

torque wrench • box-end wrench • breaker bar (flex

handle)

cheater bar • chisel • clicker-type torque wrench • cold

chisel • close end • combination wrench • crowfoot

socket

dead-blow hammer • diagonal (side-cut or dike) pliers •

double-cut file • drive size • easy out • extension

files • fitting wrench • flare-nut wrench • flat-tip (straight

blade) screwdriver • hacksaw • locking pliers

KEY TERMS:

multi-groove adjustable pliers • needle-nose pliers • nut

splitter

offset left aviation snip • offset right aviation snip •

open-end wrench • punch • ratchet • removers

screwdriver • seal driver • seal puller • single-cut file •

slip-joint pliers • snap-ring pliers • socket • socket

adapter • straight cut aviation snip • stud removal tool •

stud remover

tin snips • torque wrench • tube-nut wrench • universal

joint • utility knife • VISE GRIPS • water pump pliers •

wrench

®

Wrenches are the most used hand tool by service techs Most are

constructed of forged alloy, usually chrome-vanadium steel

The wrench is formed, hardened, tempered to reduce brittleness,

and then chrome plated There are several types of wrenches

Figure 9–1 A forged wrench after it has been forged but before the flashing, extra material

Open-End Wrench An open-end wrench is used for bolts or

nuts that do not require a lot of torque It can be easily placed on

a bolt or nut with an angle of 15 degrees

The disadvantage of an open-end wrench is lack of torque that

can be applied, as the open jaws of the wrench only contact two

flat surfaces of the fastener

An open-end wrench has two different sizes; one at each end

Figure 9–2 A typical open-end wrench The size is different on each end and notice that the

Box-End Wrench A box-end wrench, is also called a close-end

wrench, has two different sizes; one at each end It is placed over

the top of, and grips the points of the fastener

Figure 9–3 A typical box-end wrench is able

to grip the bolt or nut at points completely

around the fastener Each end is a different

size.

A box-end wrench should be used to loosen or to tighten fasteners

Figure 9–4 The end of a box-end wrench is angled 15 degrees to allow clearance for nearby objects or other fasteners.

Most service technicians purchase combination wrenches, which

are open at one end and have the same size box on the other end

Figure 9–5 A combination

wrench has an open end at one

end and a box end at the other.

A combination wrench allows the tech to loosen or tighten a

fastener using the box end of the wrench, and turn it around to

use the open end to increase the speed of rotating the fastener

Adjustable Wrench An adjustable wrench is often used where the exact

size wrench is not available or when a large nut, such as a wheel spindle nut,

needs to be rotated but not tightened.

An adjustable wrench should not be used to loosen or tighten

fasteners because the moveable jaws can loosen their grip on the

fastener, causing it to become rounded

Figure 9–6 An adjustable wrench Adjustable wrenches are sized by the overall length of the wrench and not how far the jaws open Common sizes include 8, 10, and 12 inch.

Line Wrenches Called flare-nut wrenches, fitting wrenches, or

tube-nut wrenches Designed to grip almost all the way around a nut

used to retain a fuel or refrigerant line, and yet able to be installed

over the line.

Figure 9–7 The end of a typical line wrench, which shows that it is capable of grasping most

Safe Use of Wrenches Wrenches should be inspected before use

to be sure they are not cracked, bent, or damaged They should be

cleaned after use

Always use the correct size of wrench for the fastener being

loosened or tightened to prevent the rounding of the fastener

When attempting to loosen a fastener, pull—do not push— a

wrench If a wrench is pushed, your knuckles can be hurt when

forced into another object if the fastener breaks loose

RATCHETS, SOCKETS AND EXTENSIONS

A socket fits over the fastener and grips the points and/or flats It

is rotated (driven) using either a long bar called a breaker bar

(flex handle) or a ratchet.

Figure 9–8 A typical ratchet used to rotate a socket A ratchet makes a ratcheting noise when

it is being rotated in the opposite direction from loosening or tightening A knob or lever on the

Figure 9–9 A typical flex handle used to rotate a socket, also called a breaker bar because

it usually has a longer handle than a ratchet and therefore, can be used to apply more torque

to a fastener than a ratchet.

A ratchet turns the socket in only one direction and allows the

rotating of the ratchet handle back and forth in a narrow space

Extensions and universal joints are used with sockets to allow

access to fasteners in restricted locations Sockets are available

in various drive sizes, including 1/4-inch, 3/8-inch, and 1/2-inch.

Figure 9–10 The most commonly used socket drive sizes include 1 /4 -inch, 3 /8 -inch, and

1 /2 -inch drive.

Many heavy-duty truck and/or industrial applications use 3/4 and

1-inch sizes The drive size is the distance of each side of the

square drive Sockets and ratchets of the same size are designed to

Figure 9–11 A six-point

socket fits the head of the

bolt or nut on all sides A

twelve-point socket can

round off the head of a

bolt or nut if a lot of force

is applied.

It is sometimes confusing which way to rotate a wrench or screwdriver,

especially when the head of the fastener is pointing away from you To

help visualize while looking at the fastener, say “righty-tighty, lefty-loosey.”

It is sometimes confusing which way to rotate a wrench or screwdriver,

especially when the head of the fastener is pointing away from you To

help visualize while looking at the fastener, say “righty-tighty, lefty-loosey ”

Right to Tighten

Crowfoot Sockets A crowfoot socket is a socket that is an

open-end or line wrench to allow access to fasteners that cannot be

reached using a conventional wrench Crowfoot sockets are

available in the following categories:

Fractional inch end

open-Metric open-endFractional line Metric line

Figure 9–12 A crowfoot socket is designed to reach fasteners using a ratchet or breaker bar

Torque Wrenches Socket turning handles designed to apply a

known force to the fastener are called Torque wrenches A

clicker-type torque wrench is set to the specified torque and

“clicks” when the value has been reached

When force is removed

from the handle, another

click is heard The wrench

should be set back to zero

after use and check for

calibration regularly

Figure 9–13 Using a torque wench to tighten

Figure 9–14 A beam-type torque wrench that displays the torque reading on the face of the

dial The beam display is read as the beam defects, which is in proportion to the amount of

torque applied to the fastener.

A beam-type torque wrench is used to measure torque Instead of

presetting the value, the actual torque is displayed on the dial as the fastener is tightened Beam-type wrenches are available in 1/4, 3/8,

Figure 9–15 Torque wrench calibration checker.

Torque wrenches should be checked

regularly For example, Honda has

a torque wrench calibration setup at

each of their training centers It is

expected that a torque wrench be

checked for accuracy before every

use Most experts recommend that

torque wrenches be checked and

adjusted as needed at least every

year and more often if possible

Torque wrenches should be checked

regularly For example, Honda has

a torque wrench calibration setup at

each of their training centers It is

expected that a torque wrench be

checked for accuracy before every

use Most experts recommend that

torque wrenches be checked and

adjusted as needed at least every

year and more often if possible

Check Torque Wrench

Calibration Regularly

The unit for torque is expressed as a force times the distance (leverage)

from the object Therefore, the official unit for torque is lb-ft (pound-feet)

or Newton-meters (a force times a distance) It is commonly expressed in

ft-lbs and even some torque wrenches are labeled with this unit.

The unit for torque is expressed as a force times the distance (leverage)

from the object Therefore, the official unit for torque is lb-ft (pound-feet)

or Newton-meters (a force times a distance) It is commonly expressed in

ft-lbs and even some torque wrenches are labeled with this unit.

Is it Lb-Ft or Ft-Lb or Torque?

Misreading torque specs is easy to do but can have serious damaging

results Specs for fasteners are commonly expressed lb-ft Many smaller

fasteners are tightened to specifications expressed in lb-in

1 lb-ft = 12 lb-in.

If a fastener were accidentally tightened to 24 lb-ft instead of 24 lb-in., the actual torque applied will be 288 lb-in instead of the specified 24 lb-in The extra torque will likely break the fastener, but it could also warp or distort

the part being tightened Always double-check the torque specs.

Misreading torque specs is easy to do but can have serious damaging

results Specs for fasteners are commonly expressed lb-ft Many smaller

fasteners are tightened to specifications expressed in lb-in

1 lb-ft = 12 lb-in.

If a fastener were accidentally tightened to 24 lb-ft instead of 24 lb-in., the

actual torque applied will be 288 lb-in instead of the specified 24 lb-in The extra torque will likely break the fastener, but it could also warp or distort

the part being tightened Always double-check the torque specs.

Double-Check the Specifications

Safe Use of Sockets and Ratchets Always use the proper size

socket that correctly fits the bolt or nut All sockets and ratchets

should be cleaned after use before being placed back into the

toolbox Sockets are available in short and deep well designs

Select the appropriate drive size

For small work, such as on the

dash, select a 1/4-inch drive For

most general work, use a 3/8

For suspension, steering and

other large fasteners, use a

Socket adapters are available and can be used for different drive size

sockets on a ratchet Combinations include:

Using a larger drive ratchet or breaker bar on a smaller size socket can

cause the application of too much force to the socket, which could crack

or shatter Using a smaller size drive tool on a larger socket will usually

not cause any harm, but would greatly reduce the amount of torque that

can be applied to the bolt or nut.

Socket adapters are available and can be used for different drive size

sockets on a ratchet Combinations include:

Using a larger drive ratchet or breaker bar on a smaller size socket can

cause the application of too much force to the socket, which could crack

or shatter Using a smaller size drive tool on a larger socket will usually

not cause any harm, but would greatly reduce the amount of torque that

can be applied to the bolt or nut.

Use Socket Adapters with Caution

1 /4 -inch drive — 3 /8 -inch sockets

3 /8 -inch drive — 1 /4 -inch sockets

3 /8 -inch drive — 1 /2 -inch sockets

1 /2 -inch drive — 3 /8 -inch sockets

Whenever a fastener is difficult to remove, some technicians will insert the handle of a ratchet or a breaker bar into a length of steel pipe The extra

length of the pipe allows the technician to exert more torque than can be

applied using the drive handle alone However, the extra torque can easily overload the socket and ratchet, causing them to break or shatter, which

could cause personal injury.

Whenever a fastener is difficult to remove, some technicians will insert the handle of a ratchet or a breaker bar into a length of steel pipe The extra

length of the pipe allows the technician to exert more torque than can be

applied using the drive handle alone However, the extra torque can easily overload the socket and ratchet, causing them to break or shatter, which

could cause personal injury.

Avoid Using “Cheater Bars”

Many smaller fasteners are removed and installed by using a

screw-driver, available in many sizes and tip shapes

The most commonly used is

called a flat tip or straight

blade.

Flat-tip screwdrivers are sized

by the width of the blade

This width should match the

screwdriver The width of the blade should

Another type of commonly used screwdriver is named for Henry

F Phillips, who invented the crosshead screw in 1934 Due to the

shape of the screw and screwdriver, a Phillips screw can be driven

with more torque than a slotted screw

A Phillips head screwdriver is specified by the length of the

handle and size of the point at the tip

A #1 tip has a sharp point, a #2 the most commonly used A #3 tip

is blunt and used for larger sizes of Phillips head fasteners

Both straight and Phillips screwdrivers are available with a short

CAUTION: Do not use a screwdriver as a pry tool or as a chisel Always use the proper tool for each application.

CAUTION: Do not use a screwdriver as a pry tool or as a chisel Always use the proper tool for each application.

Figure 9–18 Two stubby screwdrivers that are used to access screws that have limited space

Both straight and Phillips screwdrivers are available with a short

blade and handle for access to fasteners with limited room

Offset Screwdrivers Are used in places where a conventional

screwdriver cannot fit An offset is bent at the ends and is used

similar to a wrench Most have a straight blade at one end and a

Phillips end the other

Figure 9–19 An offset screwdriver is used to install or remove fasteners that do not have

Impact Screwdriver Is is used to break loose or tighten a screw

A hammer is used to strike the end after the screwdriver holder is

placed in the head of the screw and rotated the desired direction

The force from the blow does

two things:

It applies a force downward

holding screwdriver tip in the

slot and also applies a twisting

force to loosen (or tighten) the

screw

Figure 9–20 An impact screwdriver used to remove slotted or Phillips head fasteners that cannot be broken loose using a standard

A Canadian named P L Robertson invented the Robertson screw and

screwdriver in 1908, which uses a square-shaped tip with a slight taper

The Robertson screw-driver uses color-coded handles because different

size screws required different tip sizes The color and sizes include:

The Robertson screws are rarely found in the United States but are

common in Canada.

A Canadian named P L Robertson invented the Robertson screw and

screwdriver in 1908, which uses a square-shaped tip with a slight taper

The Robertson screw-driver uses color-coded handles because different

size screws required different tip sizes The color and sizes include:

The Robertson screws are rarely found in the United States but are

common in Canada.

What is a Robertson Screwdriver?

Orange(#00) — Number 1 and 2 screws Yellow (#0) — Number 3 and 4 screws Green (#1) — Number 5, 6, and 7 screws Red (#2) — Number 8, 9, and 10 screws Black (#3) — Number 12 and larger screws

Safe Use of Screwdrivers Always use the proper type and size

screwdriver that matches the fastener

Try to avoid pressing down on a screwdriver because if it slips,

the screwdriver tip could go into your hand, causing serious

personal injury

All screwdrivers should be cleaned after use

Do not use a screwdriver as a pry bar; always use the correct tool

for the job

HAMMERS AND MALLETS

Hammers And mallets are used to force objects together or

apart The shape of the back part of the hammer head (called the

peen) usually determines the name.

For example, a ball-peen hammer has a rounded end like a ball

and it is used to straighten oil pans and valve covers, using the

hammer head, and for shaping metal, using the ball peen

Figure 9–21

A typical ball-peen hammer.

Mallets Are a type of hammer with a large striking surface,

which allows the tech to exert force over a larger area

This helps avoid damage to parts or components

Mallets are made from a variety of materials including rubber,

plastic, or wood

A hammer is usually sized by the weight of the head of the hammer and the length of the handle For example, a commonly used ball-

A shot-filled plastic hammer is called a dead-blow hammer The

small lead balls (shot) inside a plastic head prevent bouncing of the hammer off of the object when struck

Figure 9–23 A dead-blow hammer that was left outside in freezing weather The plastic covering was damaged, which destroyed this hammer The lead shot is encased

in the metal housing and then covered.

NOTE: A claw hammer has a claw used to remove nails and is not used for automotive service.

automotive service.

Safe Use of Hammers and Mallets All mallets and hammers

should be cleaned after use and not exposed to extreme

temperatures

Never use a hammer or mallet that is damaged in any way

Always use caution to avoid doing damage to components and

surrounding areas

Slip-Joint Pliers Pliers are capable of holding, twisting, bending,

and cutting They are an extremely useful classification of tools

Common household pliers are called slip-joint pliers.

Figure 9–24 Typical slip-joint pliers, which

are also common household pliers The slip

joint allows the jaws to be opened to two

different settings.

There are two different positions where the junction of the handles

MultiGroove Adjustable Pliers For gripping larger objects,

using a set of multigroove adjustable pliers is common

Originally designed to remove various size nuts holding rope seals

used in water pumps, the name water pump pliers is also used

Figure 9–25 Multigroove adjustable pliers are known by many names, including the trade name

Figure 9–26 A linesman’s pliers are very useful because they can help perform many automotive

twisting wire While commonly used by construction workers and

electricians, they are very useful tools for the service tech who deals

with wiring

The center parts of

the jaws are designed

to grasp round objects

such as pipe or tubing

without slipping

Diagonal Pliers Are designed for cutting only The jaws are set at

an angle to make it easier to cut wires Diagonal pliers are also

called side cut or dike.

Needle-Nose Pliers Designed to grip small objects or those in

tight locations, needle-nose pliers have long, pointed jaws.

Most have a wire cutter located at the base near the pivot There

are several variations including right angle or slightly angled

jaws to allow access to cramped areas

Figure 9–28 Needle- nose pliers

are used where there is limited

access to a wire or pin that

needs installed or removed.

Locking Pliers Are adjustable pliers that can be locked to hold

objects from moving Most have wire cutters near the pivot point

The size is the length of the pliers, not how far the jaws open

Figure 9–29 Locking pliers are best known by their trade name VISE GRIPS ®

Safe Use of Pliers Pliers should not be used to remove any bolt

or other fastener They should only be used when specified by the

vehicle manufacturer