Fasteners and Threads

Question 1

Most fasteners have a thread angle of what?

Answer 1

60 degrees

Question 2

The distance from point to point on a screw to a corresponding point on the next thread, measured parallel to the axis is called what?

Answer 2

The pitch

Question 3

The distance a screw thread advances axially in one turn is called what?

Answer 3

The lead

Question 4

The surface of a thread connecting the crest to the root is called what?

Answer 4

Flank or side

Question 5

For counterclockwise rotation what kind of thread is used?

Answer 5

Left-hand thread

Question 6

In threaded fasteners the first full thread of the nut next to the flat washer takes how much of the load?

Answer 6

50 percent, the next thread 25 percent, the remaining share the rest

Question 7

What does 3/4” - 10 UNC - 2A x 1-1/2” lg mean?

Answer 7

3/4" nominal diameter
10 tpi
Unified National Coarse thread style
Class fit 2
A = external thread
1-1/2" length

Question 8

Maximum looseness in the mating threads is what class?

Answer 8

Class 1

Question 9

Average fit with little play in threads for everyday shop bolts are what class?

Answer 9

Class 2

Question 10

No looseness in mating threads are which class?

Answer 10

Class 3

Question 11

Precision threads in a micrometer is which class?

Answer 11

Class 4

Question 12

Extremely precise threads are which class?

Answer 12

Class 5&6

Question 13

60 degree thread angle with flats on the crest and root are which type of threads?

Answer 13

American National Threads - National Coarse and National Fine most common

Question 14

60 degree thread angle with a rounded root are which type of thread?

Answer 14

Unified Screw Thread

Question 15

The threads in this series have the same pitch for all diameters

Answer 15

Constant pitch series

Question 16

This thread is not for a fastener, has flat crest and roots, and a 29 degree angle. Used on a lathe

Answer 16

Acme Thread

Question 17

This tapered thread seals a joint, preventing leakage

Answer 17

National Pipe Taper (NPT)

Question 18

M8 x 1.25 x 50 mm means?

Answer 18

Metric
8 - Nominal diameter
1.25 the pitch in mm
50mm - length

Question 19

What the difference between a bolt and screw?

Answer 19

The screw is loaded by the head, and a bolt is loaded or tightened by a nut

Question 20

A rod that is threaded on both ends is called what?

Answer 20

A stud

Question 21

The head markings on a bolt head indicate what?

Answer 21

Tensile strength

Question 22

What type of bolts are used when a smooth round head is required?

Answer 22

Carriage bolts

Question 23

The most common bolt head is

Answer 23

Hexagon head bolts

Question 24

These bolt heads must be turned 90 degrees before the wrench can be relocated on the head

Answer 24

Square headed bolts

Question 25

Cap screws start at what size?

Answer 25

1/4"

Question 26

This type of nut are locking nuts that also use a cotter pin

Answer 26

Castellated nut

Question 27

These nuts withstand greater torque and a larger flat surface than a Hex nut

Answer 27

Square nut

Question 28

When used to lock a regular nut the jam nut should be between the hex nut and joint surface because?

Answer 28

The hex nut takes the full bolt load

Question 29

A thinner version of a jam nut is called?

Answer 29

Palnuts

Question 30

The size of any internal thread is identified by what?

Answer 30

The major thread diameter and thread pitch of the bolt that would fit the nut

Question 31

Machine screws come in sizes as big as

Answer 31

3/8"

Question 32

How do you find that diameter of a machine screw?

Answer 32

Start as 0.060 and add 0.013 for every screw number increase

Question 33

These are used under bolt heads to increase the bearing surface of the fastener and protect from damage

Answer 33

Flat plain washer

Question 34

These washers are used to keep nuts and bolts from becoming loose from vibration

Answer 34

Split-ring lock washers

Question 35

These are thicker and stronger than than Split washers

Answer 35

Hi-collar lock washers

Question 36

These washers use teeth and are used when extra holding power is required

Answer 36

Tooth-lock washers

Question 37

What is the ratio of a taper pin?

Answer 37

1/4" per foot (1:48)

Question 38

What are used to align two machinery parts?

Answer 38

Dowel pins

Question 39

These pins are designed to break under greater than normal loads

Answer 39

Shear pins

Question 40

These pins are hollow, oversize and compress when driven into place to hold the parts in place

Answer 40

Spring pins and roll (coiled) pins

Question 41

These pins expand when driven into place and have tremendous holding power

Answer 41

Grooved pins

Question 42

These are used instead of cotter pins when they must be removed frequently

Answer 42

Spring-locking pins (hairpin cotters)

Question 43

The three taps used for different stages of a cut

Answer 43

Taper, Plug, Bottoming

Question 44

This is used to hold the tap securely and that even forces are applied

Answer 44

Tap wrenches

Question 45

How do you determine the tap size of a hole?

Answer 45

Tap drill size = nominal diameter - pitch | Reminder, pitch =1/pitch

Question 46

What are used to cut external threads?

Answer 46

A die

Question 47

What is the proper process for using a tap?

Answer 47

Back a quarter turn, forward half a turn

Question 48

What tool is used to hold a die?

Answer 48

Die stock

Question 49

Elongation of the bolt is called

Answer 49

Tension

Question 50

The tendency of the wedge shape of the thread to enlarge the diameter of the nut is called

Answer 50

Dilation

Question 51

The amount a fastener can be stretched and still return to its original length is called

Answer 51

Elastic limit

Question 52

Where the fastener begins to take a permanent set

Answer 52

Yield point

Question 53

The failure or breaking point of a bolt

Answer 53

Ultimate tensile strength

Question 54

Tensile forces are measured in

Answer 54

per square inch (psi)

Question 55

Tightening a nut and bolt assembly to a predetermined torque value is known as

Answer 55

Preloading

Question 56

These bolts provide visual evidence that the desired preload value has been reached

Answer 56

Preload indicating bolts

Question 57

What are the types of torque wrenches?

Answer 57

Torque-limiting, dial indicating, deflecting beam

Question 58

This toque wrench is used where high torque is required to tighten fasteners

Answer 58

Hydraulic torque wrench