Torque

Question 1

____-____ torque is friction underneath the head of the bolt.

Answer 1

Static Breakaway (90% of torque distribution)

Question 2

____-____ torque is friction caused by stretching of the fastener.

Answer 2

Dynamic Applied (10% of torque distribution)

Question 3

What are the four phases of tightening a bolt?

Answer 3

1. ) Run down
2. ) Alignment
3. ) Elastic
4. ) Plastic

Question 4

Bolts are identified by size (length and diameter) and also ____.

Answer 4

Thread pitch

Question 5

Thread pitch is measured in ____.

Answer 5

TPI (Threads per Inch)

Question 6

What are benefits of having finer threads?

Answer 6

1. ) Higher torque can be applied
2. ) More precise torquing
3. ) Less torque for required tension

Question 7

In the US, standard flank on most threads is __ degrees.

Answer 7

60

Question 8

The standard metric thread is called “____ thread”

Answer 8

Coarse

Question 9

T/F: Fine threads are more expensive, and are easier to damage or cross thread.

Answer 9

True

Question 10

Shear force is usually about __ times the tensile strength.

Answer 10

.6

Question 11

What are the three common bolt grades in the US?

Answer 11

Grades 2, 5, and 8.

Question 12

The strength of metric bolts are specified by what?

Answer 12

Property Class

Question 13

A metric bolt with a property class of “8.8” means what?

Answer 13

It will break at about 800MPa, and the yield point of the bolt is roughly at 80% of 800MPa, about 640MPa

Question 14

1MPa (Mega Pascal) is equivalent to about ___ PSI.

Answer 14

145

Question 15

T/F: Nut/Bolt assemblies are designed so the threads of the nut will strip out first.

Answer 15

False, the bolt should break first.

Question 16

What are the 5 types of nuts covered in the section?

Answer 16

1. ) Hex
2. ) Stop
3. ) Free Spinning
4. ) Nut with star washer
5. ) Square Nut

Question 17

What are the 3 types of washers covered in this section?

Answer 17

1. ) Flat
2. ) Lock
3. ) Lock with internal teeth

Question 18

What are the three types of bolts covered in this section?

Answer 18

1. ) Hex
2. ) Hex with serrated flange
3. ) Carriage bolt

Question 19

What are the four types of torque wrenches?

Answer 19

1. ) Beam
2. ) Dial
3. ) Clicker
4. ) Electronic

Question 20

Torque wrenches should always be placed at their ___ setting for storing until next use.

Answer 20

Lowest

Question 21

A torque wrench should only be used between __-__% of its rated capacity.

Answer 21

30-80%

Question 22

What are the three common ratios for torque multipliers?

Answer 22

3:1, 4:1, 5:1

Question 23

A calibrated clicker-style torque wrench should be as accurate as plus or minus __%.

Answer 23

4%

Question 24

A calibrated electronic torque wrench should be as accurate as plus or minus __%.

Answer 24

2%

Question 25

Electronic torque wrenches indicate a ____ light when within 10% of target torque, ____ when within 4% of target, and ____ when 4% over target.

Answer 25

Yellow - within 10% Green - within 4% Red - over by 4%

Question 26

T/F: The head of a bolt is included when considering its length.

Answer 26

False.

Question 27

The top and bottom of the thread notch are called the ___ and ___, respectively.

Answer 27

Crest and Root

Question 28

The area between the crest and root of a thread notch is called the ____.

Answer 28

Flank

Question 29

Some bolts have an unthreaded portion that is between the head and the threads called the ____.

Answer 29

Shank