Knowledge

Reference Guide – Hexagonal bolts

Posted by author-avatar
On September 12, 2024
0 comments

Purpose of Using Different Bolt Grades:

  • Grade 5: These bolts are medium strength and are commonly used in automotive applications, machinery, and equipment. They offer a balance between strength and flexibility, making them suitable for general-purpose fastening where high tensile strength is not critical.
  • Grade 8: These are high-strength bolts used in demanding applications such as heavy machinery, high-stress environments, and structural applications. They have higher tensile strength than Grade 5 bolts and are ideal for situations where higher loads and stresses are expected.
  • Grade L9: These bolts are the highest-strength fasteners available in standard hex-head designs. Grade L9 is used for extreme stress and high-load applications, such as in heavy construction equipment, automotive suspensions, and industrial machinery, where maximum strength is essential.

Diameter (inches)

Common Lengths (inches)

Thread Type

Thread Pitch (TPI)

Torque (Grade 5) (ft-lbs)

Torque (Grade 8) (ft-lbs)

Torque (Grade L9) (ft-lbs)

Drill Size (inches)

Across Flats (inches)

1/4

1/2 - 6

UNC

20.0

8

12

14

13/64

7/16

1/4

1/2 - 6

UNF

28.0

8

12

14

13/64

7/16

5/16

1/2 - 6

UNC

18.0

17

24

30

1/4

1/2

5/16

1/2 - 6

UNF

24.0

17

24

30

1/4

1/2

3/8

1/2 - 6

UNC

16.0

31

46

55

5/16

9/16

3/8

1/2 - 6

UNF

24.0

31

46

55

5/16

9/16

7/16

1/2 - 6

UNC

14.0

50

78

92

23/64

5/8

7/16

1/2 - 6

UNF

20.0

50

78

92

23/64

5/8

1/2

1/2 - 6

UNC

13.0

75

115

135

27/64

3/4

1/2

1/2 - 6

UNF

20.0

75

115

135

27/64

3/4

9/16

1/2 - 6

UNC

12.0

110

165

195

31/64

13/16

9/16

1/2 - 6

UNF

18.0

110

165

195

31/64

13/16

5/8

1/2 - 6

UNC

11.0

150

225

270

17/32

15/16

5/8

1/2 - 6

UNF

18.0

150

225

270

17/32

15/16

3/4

1/2 - 6

UNC

10.0

260

380

450

21/32

1-1/8

3/4

1/2 - 6

UNF

16.0

260

380

450

21/32

1-1/8

7/8

1/2 - 6

UNC

9.0

400

600

720

49/64

1-5/16

7/8

1/2 - 6

UNF

14.0

400

600

720

49/64

1-5/16

1

1/2 - 6

UNC

8.0

580

900

1080

7/8

1-1/2

1

1/2 - 6

UNF

12.0

580

900

1080

7/8

1-1/2

1-1/8

1/2 - 6

UNC

7.0

800

1280

1500

31/32

1-11/16

1-1/8

1/2 - 6

UNF

12.0

800

1280

1500

31/32

1-11/16

1-1/4

1/2 - 6

UNC

7.0

1120

1820

2160

1-1/16

1-7/8

1-1/4

1/2 - 6

UNF

12.0

1120

1820

2160

1-1/16

1-7/8

1-1/2

1/2 - 6

UNC

6.0

1940

3000

3600

1-11/32

2-1/4

1-1/2

1/2 - 6

UNF

12.0

1940

3000

3600

1-11/32

2-1/4

1-3/4

1/2 - 6

UNC

5.0

2800

4400

5280

1-17/32

2-3/4

1-3/4

1/2 - 6

UNF

12.0

2800

4400

5280

1-17/32

2-3/4

2

1/2 - 6

UNC

4.5

4000

6400

7680

1-3/4

3

2

1/2 - 6

UNF

12.0

4000

6400

7680

1-3/4

3

Notes:

  • Tensile Strength:
  • Grade 5: 120,000 psi
  • Grade 8: 150,000 psi
  • Grade L9: 180,000 psi
  • Head Markings (Number of Radial Lines):
  • Grade 5: 3 radial lines
  • Grade 8: 6 radial lines
  • Grade L9: 9 radial lines
Newer Reference guide – Rivnuts (Metric and Imperial)
Back to list
Older Maximizing Efficiency and Safety with Grade 70 Chains, Hooks, and Tensioners