MODULE 6

Question 1

is any device used to connect or join two or more components

Answer 1

Fasteners

Question 2

It is formed by cutting a continousu helical groove on a cylindrical surface

Answer 2

screw thread

Question 3

A screw made by cutting a single helical groove on the cylinder is known as

Answer 3

Single threaded or single starscre

Question 4

second thread is cut in the space between the grooves of the first.

Answer 4

double threaded or double start screw is formed

Question 5

The helical grooves may be cut either -

Answer 5

right hand or left hand

Question 6

What is the difference between a bolt and screw?

Answer 6

A bolt is a threaded fasteners designed to pass through holes in the mating members and to be secured by tightening a nut from the end opposite the head of the bolt but the screw is a threaded fastener designed to be inserted through a hole in mating member

Question 7

What is a threaded fastener designed to pass through holes in the mating members and to be secured by tightening a nut from the end opposite the head of the bolt?

Answer 7

bolt

Question 8

It is a threaded fastener designed to be inserted through a hole in one member to be joined into a threaded hole in mating member?

Answer 8

screw

Question 9

The threaded hole may be pre-formed, by tapping, or it may be formed by the screw itself as it is forced into material.

Answer 9

screw

Question 10

It is the largest diameter of and external or internal screw thread

Answer 10

Major Diameter

Question 11

The screw is specified by this diameter. It is also known as outside or nominal diameter.

Answer 11

Major Diameter

Question 12

It is the smallest diameter of an external or internal screw thread

Answer 12

Minor Diameter

Question 13

It is also known as core or root diameter

Answer 13

Minor Diameter

Question 14

It is the diameter of an imaginary cylinder , on a cylindrical screw thread, the surface of which would pass through the thread at such point as to make equal the width of the thread and the width of the spaces between the thread.

Answer 14

Pitch diameter

Question 15

It is called _____ at which the RIDGES ON THE BOLT are in complete touch with the ridges of the corresponding nut.

Answer 15

effective diameter

Question 16

It is the distaance from the point of one thread to the corresponding point on the next.

Answer 16

Pitch

Question 17

This is measured as the axial direction between corresponding points in the same axial plane.

Answer 17

Pitch

Question 18

It is the distance between two corresponding points on the same helix.

Answer 18

Lead

Question 19

It is also defined as the distance in which the screw thread advances axially in one rotation of the nut.

Answer 19

Lead

Question 20

It is qual to the pitch in case of single start threads, it is twice the pitch in double start thread, trice the pitch in triple start and so on.

Answer 20

Lead

Question 21

It is a screw made a single helical groove on the cylinder

Answer 21

Single Threaded(or single-start)

Question 22

If the second thread is cut in the space between the grooves of the first

Answer 22

Double Threaded or Double Start Screw

Question 23

It is the top surface of the thread

Answer 23

Crest

Question 24

It is the bottom surface created by the two adjacent flank of the thread

Answer 24

Angle of Thread

Question 25

It is the imaginary circle whose diameter is the mean of the pitch and minor diameters

Answer 25

Stress Area

Question 26

What are the two identification symbols?

Answer 26

1. American National Thread and Unified Thread Series 2.Metric Thread Series

Question 27

What is an example of American National Thread and Unified Thread Seried?

Answer 27

1 - 8 UNC-2A- RH

Question 28

In 1 - 8 UNC-2A- RH, what does 1 mean?

Answer 28

Nominal Size or Major Diameter

Question 29

In 1 - 8 UNC-2A- RH, what does 8 mean?

Answer 29

No. of threads per inch

Question 30

In 1 - 8 UNC-2A- RH, what does UNC mean?

Answer 30

it means course thread

Question 31

What are the different thread classifications and their symbols?

Answer 31

UNC - coarse thread UNF fine thread UNEF - Extra Fine thread

Question 32

In 1 - 8 UNC-2A- RH, what does 2 in 2A mean?

Answer 32

It means the tolerance

Question 33

what are the symbols for tolerance and fit for the american national thread and unified series?

Answer 33

1 - widest tolerance 2 - normal fir 3 - closest fit

Question 34

In 1 - 8 UNC-2A- RH, what does A in 2A mean?

Answer 34

It means external thread

Question 35

What does A and B means in American National Thread and Unified Thread Series?

Answer 35

A - external thread B - internal thread

Question 36

What does Rh and LH means in American National Thread and Unified Thread Series?

Answer 36

Right Hand Threaded And Left Hand Threaded

Question 37

Can you give an example of Metric Thread Series?

Answer 37

M 16 x 2 - 6g

Question 38

What is M in M 16 x 2 - 6g?

Answer 38

It stands for Metric Thread Series

Question 39

What is 16 in M 16 x 2 - 6g?

Answer 39

It is the Nominal Size or Major Diameter in mm

Question 40

What is 2 in M 16 x 2 - 6g?

Answer 40

It is the pitch in mm/thread

Question 41

What is 6 in M 16 x 2 - 6g?

Answer 41

It is the tolerance

Question 42

What is g in M 16 x 2 - 6g?

Answer 42

It is the external thread

Question 43

What does the external thread and internal thread symbolizes in Metric Thread Series?

Answer 43

g and h

Question 44

What are the different kind of threads?

Answer 44

V- thread, Sellers Thread, Whitworth Thread

Question 45

It has a sharp crest and root

Answer 45

V-thread

Question 46

Occasionally cut on lathes are undesirable because the thin material is easily damage and the concentration of the stresses are the root of the thread is large

Answer 46

V-thread

Question 47

Who proposed the form with flat crest and root, which partially removes the inherent weakness of the V threads?

Answer 47

William Seller(1864)

Question 48

It was the US Standard for so many years

Answer 48

Sellers Thread

Question 49

It features a rounded crest and roots.

Answer 49

Whitworth Thread

Question 50

This thread has been the standard of Britain

Answer 50

Whitworth Thread

Question 51

It has better fatigue strength than the Sellers thread because of the rounded roots.

Answer 51

Whitworth Thread

Question 52

What are the different standard threads?

Answer 52

Coarse Thread Series, UNC Fine Thread Series, UNF Extra Fine SEries, UNEF 8 THREAD SERIES, UN

Question 53

Recommended for the general use; where jar and vibration are not important factors, where disassembly of parts are frequent , and where tapped holes are metals other than steel.

Answer 53

Coarse Thread Series, UNC

Question 54

Frequently used in automobile and aircraft works; especially where jar and vibration(tending to loosen the nut) are present, where a fine adjustment is required with the use of castle nut and where tapped holes are on steel.

Answer 54

Fine Thread Series, UNF

Question 55

Partially useful in aeronautical equipment, suitable where thin walled material is to be threaded , where fine adjustment are required and where jar and vibration is excessive?

Answer 55

Extra Fine Thread Series,

Question 56

Screw with this thread are likely to be made of heat-treated alloy steel

Answer 56

Extra Fine Thread Series, UNEF

Question 57

It is used on bolts for high-pressure pipes flanges, cylinder head studs,etc

Answer 57

8 Thread Series, 8 UN

Question 58

It is the relationship existing between two corresponding external and internal threads with respect to the amount of clearance or interference which is present when they are assembled

Answer 58

Fits

Question 59

It has the widest tolerance and is used where quick and easy assembly, even with bruised thread, is necessary, as in ordinance

Answer 59

Class 1A and 1B

Question 60

With tolerance suitable for normal production practices, are most widely used.

Answer 60

Class 2A and 2B

Question 61

Clearance for this fit minimizes galling and seizing in highly tightened joints and in hig-temperature applications and it is also accomodating plating

Answer 61

Class 2A and 2B

Question 62

Use this class unless there is a reason for using another.

Answer 62

Class 2A and 2B

Question 63

It provides a clearance when mated with any class of internal thread

Answer 63

Class 2A

Question 64

have the closest fit; allowance(but not the clearance) is zero.

Answer 64

Class 3A and 3B

Question 65

These classes are intended for applications when closeness of fit and high accuracy is essential

Answer 65

Class 3A and 3B

Question 66

An old name for unfinished through bolt, comes with a square, hexagonal, or rounded head and with coarse or fine threads

Answer 66

Machine Bolt

Question 67

is finished all over, usually having coarse threads

Answer 67

Coupling Bolt

Question 68

Also finished all over and has fine UNF threads, usually made of heat treated steel, and frequently has castle nut

Answer 68

Automobile Bolt

Question 69

Also falls in the same class being finished all over. It comes in a variety of heads; hexagonal, fillister, button, flathead, and hollow heads

Answer 69

Cap Screw

Question 70

Is distinguished by a short portion of the shank underneath the head being square or finned or ribbed.

Answer 70

Carriage bolts

Question 71

Originally intended for wood, this bolt is found useful where, for example, the square part fits into a square hole and prevents the screw from turning while the nut is tightened.

Answer 71

Carriage Bolts

Question 72

Provide a place for a hook for lifting parts

Answer 72

Eye Bolts

Question 73

are among the most widely used types.

Answer 73

Stud Bolts

Question 74

They are threaded on both on both ends and can be used where a through bolt is impossible.

Answer 74

Stud Bolts

Question 75

are also used as through bolt with nuts on both ends

Answer 75

Studs

Question 76

It is a cheap variety of bolt made in small sizes.

Answer 76

Stove Bolts

Question 77

These are also made in small sizes, but they are more accurately made than stove bolts.

Answer 77

Machine Screw

Question 78

These are finished all over, have fine and course thread and various heads.

Answer 78

Machine Screw

Question 79

The length of a machine screw is the distance from the ends of the screw to the most distant point of contact of the head with material being clamp

Answer 79

Machine Screw

Question 80

Have proven to be economical in many assembly operations involving plastics, die casting and sheet metals.

Answer 80

Self Tapping Screw

Question 81

Type A and Z are applies with a

Answer 81

screwdriver

Question 82

These are used as holding clamps as on an automobile springs(leaf springs).

Answer 82

U-bolts

Question 83

It is large wood screw

Answer 83

Lag Screw

Question 84

It is used to fasten machinery and equipment to a wooden base

Answer 84

Lag Screw

Question 85

On the account of its size, it has square or hexagonal head allowing it to be turned with a wrench.

Answer 85

Lag Screw

Question 86

Is a convenient device used to adjust the length o tie rods, etc.

Answer 86

Turnbuckle

Question 87

It is used to prevent motion between two parts that tend to slide over one another. They are obtainable with several combination of point and heads

Answer 87

Set Screw

Question 88

Provide a place for hook for lifting parts

Answer 88

Eye Bolts

Question 89

are among the most widely used parts

Answer 89

Stud Bolts

Question 90

They are threaded on both ends and can be used where a through bolt is impossible; for example, in bolting a head on an engine where the holes in the block are threaded.

Answer 90

Stud Bolts

Question 91

This practice is especially desirable if the hole is in weak or brittle material because the studs can be left in place when the head is removed, thus saving wear and tear on the hole.

Answer 91

Stud Bolts

Question 92

are also used as through bolts with nuts on both ends

Answer 92

Stud bolts

Question 93

It is used as through bolts with nuts on both ends

Answer 93

Studs

Question 94

It is a cheap variety of bolt made in small sizes

Answer 94

Stove Bolts

Question 95

These are also made in small sizes, but they are more accurately made than stove bolts

Answer 95

Machine Screw

Question 97

These are finished all over, have fine and course threads and various heads

Answer 97

Machine Screw

Question 98

The length of a ______ is the distance from the end of the screw to the most distant point of contact of the hear with the material being clamp.

Answer 98

Machine Screw

Question 99

Have proven to be economical in many assembly operations involving plastics, die casting and sheet metals.

Answer 99

Self-Tapping Screw

Question 100

What self-tapping screw are applied with a screwdriver?

Answer 100

Type A and Z

Question 101

What self-tapping screw is applied in standard thread pitches with fluted threads at the start for the purpose of cutting its own threads as it moves intro drilled hole?

Answer 101

Type F

Question 102

These are used as holding clamps as on automobile springs

Answer 102

U-bolts

Question 103

Is used to prevent relative motion between two parts that tend to slide over one another. They are obtainable with several combination of points and heads.

Answer 103

Set Screw