Threaded fasteners and locking devices (160103f)

Question 1

The difference between a screw and a bolt is the:

Answer 1

application

Question 2

Why are thread forming screws used?

Answer 2

They are convenient in sheet metal assemblies.

Question 3

The major diameter of a thread is shown on a drawing as 0.748 =/- .002 inch. What is the tolerance on the major diameter?

Answer 3

0.004 inch

Question 4

The pitch diameter of a thread is measured exactly halfway between the major and minor diameters. True or false.

Answer 4

False. The pitch diameter is the diameter at which the thread thickness equals the thickness of the space between the threads. It is approximately half way between the major and minor diameters.

Question 5

On a general purpose ISO metric thread, what character in the designation indicates a medium tolerance grade?

Answer 5

Number 6

Question 6

Name two taper thread forms.

Answer 6

• National Pipe Taper (NPT)
• Dryseal National Pipe Taper Fuel (NPTF)
• American Petroleum Institute (API)

Question 7

Mark on the head of a bolt indicate the _____

Answer 7

grade and tensile strength.

Question 8

The thread angle from an American National Acme thread is:

Answer 8

29°

Question 9

A no go ring gauge is easily identified by;

Answer 9

annular ring on the knurled surface.

Question 10

Thread composition gauges use the ___________ as a basis for thread sizes.

Answer 10

pitch diameter

Question 11

Rolled threads are advantageous over machined threads because:

Answer 11

• They have increased tensile strength
• They produce a burnished thread finish
• They have better wear resistance which reduces fatigue and shear problems

Question 12

The three hand taps found in a set are the:

Answer 12

Taper, plug and bottoming

Question 13

For what does API stand?

Answer 13

American Petroleum Institute