6.5

Question 1

What is the definition of a screw thread?

Answer 1

The ridge left when a groove is cut into a cylindrical surface

Question 2

What is the name for a thread if it is on the outside?

Answer 2

External or male thread

Question 3

What is the name of a thread if it is inside the material?

Answer 3

Internal or female thread

Question 4

When a thread is cut clockwise what is it called?

Answer 4

Right hand thread

Question 5

What is a thread called if it is cut anti-clockwise?

Answer 5

Left hand thread

Question 6

What is the crest of a thread?

Answer 6

The top point of the thread groove

Question 7

What is the root of a thread?

Answer 7

The bottom of the thread

Question 8

What is the flank of a thread?

Answer 8

The slope between root and crest

Question 9

What is thread angle?

Answer 9

The angle between adjacent flanks

Question 10

What is the major diameter of the thread?

Answer 10

The biggest diameter of the thread

Question 11

What is the minor diameter of the thread?

Answer 11

The smallest diameter of the thread

Question 12

What is the depth of a thread?

Answer 12

The radial distance between root and crest

Question 13

What is the pitch of a thread?

Answer 13

Distance between crest-crest or root-root

Question 14

What is the run-out of the thread?

Answer 14

The part where the minor diameter increases till it equals the major diameter

Question 15

What is meant by multiple start threads?

Answer 15

When two or more start threads are cut side by side

Question 16

What is lead of a thread?

Answer 16

The distance the thread has move in one complete rotation

Question 17

What screw systems were used in Britain?

Answer 17

British standard (BS) and British association (BA)

Question 18

Who designed the unified thread system?

Answer 18

International organisation for standardisation

Question 19

What does BSW stand for in relation to fasteners?

Answer 19

British standard whitworth

Question 20

What does BSF stand for in relation to fasteners?

Answer 20

British standard fine

Question 21

What does BSP stand for in relation to fasteners?

Answer 21

British standard pipe

Question 22

When is British standard whitworth BSW used?

Answer 22

For general purpose work in metal and plastics

Question 23

When is British standard fine BSF used?

Answer 23

Anywhere with high vibration due to its smaller thread

Question 24

When is British standard pipe BSP used?

Answer 24

When working on pipeline couplings

Question 25

What are the three types of unified thread?

Answer 25

UNC- unified national coarse
UNF- unified national fine
UNEF- unified national extra fine

Question 26

What is the thread angle of a British standard whitworth?

Answer 26

55°

Question 27

What is the thread angle of a British association?

Answer 27

47.5°

Question 28

What angle is used in American threads?

Answer 28

60°

Question 29

What is the thread angle in the unified thread system?

Answer 29

60°

Question 30

What is meant by a thread having a coarse pitch?

Answer 30

It has a greater lead (deeper but less threads)

Question 31

What is meant by a thread having a fine pitch?

Answer 31

It has a smaller lead (more but shallow threads)

Question 32

Why is having a fine pitch thread better than a coarse pitch?

Answer 32

• stronger root
• finer adjustment
• higher vibration resistance

Question 33

What is a screw pitch gauge?

Answer 33

A gauge that allows you to quickly know the thread pitch

Question 34

When are the square, buttress, acme threads used?

Answer 34

When transmission is needed such as lifting or screw jacks

Question 35

What is special about the buttress thread type?

Answer 35

It can only transmit power in one direction