Chapter 3, Summary

Question 1

What kinds of conditions are fasteners that are used in assembly of small gasoline engines, exposed to?

Answer 1

Heating and
cooling,
cyclic loading,
tensile loads,
shear loads,
corrosion, and
vibration during engine operation.

Question 2

When disassembling an engine, why is it vital to note the location of all parts, fasteners, and washers

Answer 2

so they can be replaced in proper location

Question 3

Damaged fasteners should be repalaced with new ones.

Answer 3

Lightly rusted fasteners may be cleaned and examined for reuse.

Question 4

[______] are threaded fasteners that hold parts together by squeezing them between the [____] head on one end and a nut on the other

Answer 4

Bolts

Question 5

Q: Why is a lock washer often placed between the face of a nut and the part surface?

Answer 5

A: To prevent loosening caused by vibration.

Question 6

Nuts vary in shape and size depending on what?

Answer 6

Their intended function.

Question 7

The most common nuts are:

Answer 7

Plain hexagon nuts

Question 8

Name 5 other types of nuts

Answer 8

wing nuts,
castle nuts,
acorn nuts,
jam nuts, and
various self locking nuts

Question 9

Bolt terminology includes:

Answer 9

Major diameter,
head size,
length,
and thread pitch.

Question 10

Bolt grades are related to :

Answer 10

The minimum tensile strength of the bolt.

Question 11

Bolt heads are marked with symbols to identify what?

Answer 11

The grade of the bolt.

Question 12

Thread types of signifigance for small gas engines are :

Answer 12

Unified National Coarse ( UNC)
Unified National Fine ( UNF)
Metric (M)

Question 13

Threads of a bolt or screw must be the same as :

Answer 13

The mating thread in the hole or nut.

Question 14

Threads are identified by what?

Answer 14

A thread designation.

Question 15

2 examples of thread designatiins are:

Answer 15

1/2-13 UNC-2A For standard threads,
and M10 ×1.5×25 for metric threads.

Question 16

How do screws hold parts together?

Answer 16

By passing through one part and threading into another.

Question 17

Bolts, nuts and screws on engines should be tightened according to specifications, using what?

Answer 17

A torque wrench.

Question 18

How can threads be repaired?

Answer 18

by chasing them with a threading tap for holes -or-
a threading die for bolts and screws

Question 19

When tapping new threads, how di you determine the proper size of the hole to be drilled?

Answer 19

From a tap drill chart.

Question 20

Flat washers are used to do what?

Answer 20

Provide a bearing surface for bolt and screw heads and nuts.

Question 21

Various types of lock washers do what?

Answer 21

Prevent loosening of bolts and screws

Question 22

What type of pins are used to secure castle nuts and clevis pins?

Answer 22

Cotter pins

Question 23

[—-] and [—-] are used for alignment of parts and should fit quite snugly.

Answer 23

Dowel pins and straight pins

Question 24

How are grooved pins placed into what kind of holes?

Answer 24

They are driven into interference fit holes.

Question 25

The [-----] are cut into the walss of the hole to secure the pin.

Answer 25

Grooves

Question 26

what pins have a taper along their entire length.

Answer 26

Taper Pins

Question 27

Taper pins are used for what purpose?

Answer 27

Fastening pulleys and gears to shafts to prevent slipping around the shaft.

Question 28

[----------] are circular spring steel fasteners that fit into a groove around a shaft or in a hole.

Answer 28

Retaining rings

Question 29

What kind of tool is used to install and remove retaining rings?

Answer 29

A special plier-like tool

Question 30

[----] are used on shafts that havd a gear, pulley or sleeve that fits and rotates with the shaft

Answer 30

Keys

Question 31

Keys rest in what ?

Answer 31

the keyseat, and keyway.

Question 32

Many types of [----] and [----] are used on engines and implements.

Answer 32

Adhesives and sealants.

Question 33

Thread locking compounds are used for what purpose?

Answer 33

Preventing threaded fasteners from loosening due to vibration.

Question 34

Some [---------------] are used to prevent leakage between parts.

Answer 34

Liquid sealants.

Question 35

What is important to do when using liquid sealants?

Answer 35

Use the correct onr as specified by the manufacturer.

Question 36

What are Antiseize compounds ?

Answer 36

Lubricants that prevent parts from locking together.

Question 37

What are used to seal between engine parts to prevent leakage of engine oil, coolant, compression, and vacuum?

Answer 37

Gaskets

Question 38

What is important to consider when replacing a gasket?

Answer 38

Selecting the cirrect material, shape, and thickness.

Question 39

The unthreaded part of a bolt or screw is called the:

Answer 39

Shank

Question 40

The helical portion of a bolt or screw is called the:

Answer 40

Thread

Question 41

A type of hardened screw that makes its own threads, usually found in sheet metal, is a[------] screw

Answer 41

Self tapping

Question 42

(?)The term bolt implies the use of a [-----]

Answer 42

Nut?

Question 43

Jam nuts are usually used with [----] nuts.

Answer 43

Hexagon

Question 44

The proper thread notation fir a 14 millimeter thread with a 1.5 millimeter pitch on a screw that is 40 millimeters long is[-------------------]

Answer 44

[B] M-14 × 1.5 × 40

Question 45

The proccess of cutting new threads into a hole is called :

Answer 45

A: Tapping

Question 46

T or F: For cutting threads in a through hole, the proper tap to use would be a taper tap?

Answer 46

True

Question 47

The cutting tool used to cut external tgreads is called A:

Answer 47

Die / inside a die stock handle.

Question 48

To provide a wider bearing surface for a bolt head or nut, a [------] washer should be used.

Answer 48

Flat

Question 49

(?) [True or False] If a 1/8" rolled pin is to be used in a shaft, the correct drill size to use for drilling the hole for this pin should be 3/16" diameter.

Answer 49

[?] False

Question 50

What type of fasteners are used to lock castle nuts?

Answer 50

A: Cotter pins

Question 51

[True or False] Retaining rings are made of spring steel.

Answer 51

True

Question 52

[----------] can be applied to the threads of nuts, bolts, or screws to prevent them from loosening during service.

Answer 52

B: Thread adhesive

Question 53

Gaskets are used between engine parts to seal and prevent leakage of all the following except:[-----]

Answer 53

D: Sealant

Question 54

How do you use a screw extractor to remove a fastener that has broken off below the surface it is threaded into:

Answer 54

Drill a hole approximately one half of the broken fasteners diameter at top center of it. Then tap the extractor into the hole using a hammer; The spirals on the extractor cause it to wedge tightly into the broken fastener. Use a wrench or socket to grip the extractor and back the broken fastener out if the hole.

Question 55

If a hole goes all the way through it is called:

Answer 55

A through hole.

Question 56

Holes that do not go all the way through the matrerial are called:

Answer 56

Blind holes

Question 57

Answer the folowing questions about the thread notation given below: A: 3/8-16 UNC 1A

Answer 57

B: The major diameter of the thread is: (3/8") C: How many threads per lineal inch are there?: (16) D: Is the thread coarse or fine?: (Coarse) E: Is the thread internal or external?:(External) F: Is the thread a Loose, average, or close fit? ( Loose)

Question 58

When tightening bolts on an engine head, why is it important to use a crisscross pattern unless a different pattern is specified by the manufacturer?

Answer 58

This procedure produces even gasket compression and sealing, and prevents possible warping of parts.

Question 59

When reassembling an engine, it is recommended that cotter pins be replaced rather than reused. Why should you never reuse a cotter pin?

Answer 59

Because it will have weakened from being bent, and might possibly break.

Question 60

Form- in - place sealants can be used in place of coventional gaskets. What are the advantages and disadvantages of using a sealant instead of a conventional gasket?

Answer 60

Advantages: lessens need to stock various sizes and shapes of gaskets.Increases seal strength. Improved reliabilty. Reduced cost, easier application. Disadvantages: Anerobic sealants not good for high heat applications above 200°C. Silicone sealants can have Poor resistance to fuel and aromatic solvents. Not recommended for high pressure applications.

Question 61

UNC

Answer 61

Unified National Coarse

Question 62

UNF

Answer 62

Unified National Fine