Fasteners and threads

Question 1

What are the two angles that make a cutting edge?

Answer 1

Clearance angle and rake angle

Question 2

Describe the parts of this Tap (1/2-20-UNF-2B)

Answer 2

1/2 inch is major diameter, 20 is threads per inch, UNF is unified FINE thread, 2 is your allowance and B is internal thread

Question 3

What are the purposes of threads?

Answer 3

To transmit power and increase force, to control movement, to convey material, to hold parts together, to form a pressure tight joint, to measuring

Question 4

What are external threads?

Answer 4

Threads on the outside of a fastener or part

Question 5

What are internal threads?

Answer 5

Threads on the outside of a cylinder ( example would be a bolt or screw)

Question 6

What is TPI ?

Answer 6

Threads per inch (Count the threads per inch on a bolt or screw)

Question 7

What is major diameter?

Answer 7

The width from one side of the threads to the other side of the threads (this applies to internal and external threads)

Question 8

What is minor diameter?

Answer 8

The smallest width from the inside of one side of the thread to the other

Question 9

What is Allowance vs Tolerance?

Answer 9

Allowance is the pre determined space to allow for the proper fit in the internal and outside diameter that are meeting. Tolerance is the total permissible variance given by the maximum and minimum sizes of the part

Question 10

How do they depict a left hand thread vs right hand thread.

Answer 10

On the thread code it will state LH for left hand and nothing for right hand.

Question 11

What does the C or F stand for in UNC and UNF

Answer 11

C stand for coarse and F stands for fine (this refers’s to you pitch (TPI))

Question 12

What are the three types of taps in a set?

Answer 12

Taper, Plug and Bottoming

Question 13

What are serial taps used for?

Answer 13

they are used on hard to tap material

Question 14

What shape are pipe thread?

Answer 14

tapered threads

Question 15

Where you measure the minor diameter is called on a thread?

Answer 15

the root (bottom of the thread)

Question 16

where you measure the major diameter from on a thread?

Answer 16

the crest (furthest width of the thread)

Question 17

What are the parts of a hand reamer?

Answer 17

Square, shanks, neck, flutes, chamfer

Question 18

Machine reamer vs hand reamer, what are tell tail signs to differentiate?

Answer 18

Square end on hand reamer and tapered shank on machine reamer.

Question 19

How much material do you want to be taking off with a reamer?

Answer 19

0.001 - 0.005 thousandth’s

Question 20

What direction do you rotate reamers?

Answer 20

clockwise

Question 21

What is the difference between a through hole and a blind hole?

Answer 21

Through holes go right through a workpiece where blind holes bottom out inside the piece

Question 22

How much taper per foot do reamers have?

Answer 22

1/4 (quater) inch per foot

Question 23

ferrous vs non ferrous metals?

Answer 23

Ferrous metals are magnetic and contain iron. This is a simple way to put it

Question 24

Why are the flutes off set on hand or machine reamers?

Answer 24

To prevent harmonics

Question 25

How far do broaching teeth step forward

Answer 25

0.003 of an inch

Question 26

What are the first number on metric screws for? (example M8)

Answer 26

The M states that its metric and the 8 stands for the metric diameter

Question 27

What is the size in taper per foot for pipe thread?