Screw Fasteners

Question 1

Describe Parts of the Bolt

Answer 1

Shank: Base of head to Runout
Grip length: Length of Shank
Nominal Length: Base of the head to the bottom of thread
Radius: Radius of the Shank

Question 2

Bolt Strength Classes

Answer 2

Stamped on the bolt head
Made to an industrial standard
Classes:
8.8 - Medium carbon steel, quenched and tempered
10.9 - Alloy steel, Quenched and tempered
12.9 - Alloy steel, Quenched and tempered
A-2 - Steel alloy with 17% - 19% Chromium and 8% - 13% Nickel

Question 3

Steel Strength

Answer 3

Yield Strength - The limit of elastic behaviour
Tensile Strength - Max limit before failing

Question 4

Dowels

Answer 4

Solid hard pins that align the bodies before fitting the bolts, sometimes tension load pins but they are less accurate

Question 5

Allen Key Threaded Fasteners

Answer 5

Mostly used on machinery/tooling,
Capscrews: General mechanical machining, very high strength
Countersunk head machine screw: Very High strength, small key size
Shoulder Bolt: Ground Shank, Very high strength, Precision alignment

Question 6

Standard nuts

Answer 6

Castle nut - locked with pin, visual confirmation its secure
Wing nut - Finger Tighten
Tee nut - Used for soft material like wood
Cap nut - Cosmetic, safety
Nylock
Flange nut

Question 7

Wire tied

Answer 7

Tie the nuts together to ensure they don’t come out, used in aircrafts, reliable and visual