5-3
October 2014 | Revision 1.0
Meridian Manufacturing, Inc.
5.3 BOLT SPECIFICATIONS
WARNING
EQUIPMENT FAILURE
The torque value for bolts and capscrews are
identified by their head markings. Replacing
higher “Grade” bolts (Grade 8) with lower
Grade bolts (Grade 5) will lead to equipment
failure and can result in injury or death. Always
use replacement bolts with the same Grade
markings as the removed bolt.
5.3.1 Bolt Torque Values
Torque figures indicated below are valid for non-
greased or non-oiled threads and heads unless
otherwise specified. Therefore, do not grease or
oil bolts or capscrews unless otherwise instructed
in this manual. When using locking elements,
increase torque values by 5%.
Bolt
Diameter “A”
SAE Grade 2
N·m (ft-lbs)
SAE Grade 5
N·m (ft-lbs)
SAE Grade 8
N·m (ft-lbs)
1/4"
8
(6)
12
(9)
17
(12)
5/16"
13
(10)
25
(19)
36
(27)
3/8"
27
(20)
45
(33)
63
(45)
7/16"
41
(30)
72
(53)
100
(75)
1/2"
61
(45)
110
(80)
155
(115)
9/16"
95
(70)
155
(115)
220
(165)
5/8"
128
(95)
215
(160)
305
(220)
3/4"
225
(165)
390
(290)
540
(400)
7/8"
230
(170)
570
(420)
880
(650)
1"
345
(225)
850
(630)
1320
(970)
5.3.2
Grade Markings Chart
No Marking
Grade 2
Low or Medium
Carbon Steel
Grade 5
Medium Carbon
Steel Quenched
and Tempered
Grade 8
Medium Carbon
Alloy Steel,
Quenched and
Tempered
3 Radial Lines
6 Radial Lines
Chapter 5 | Specifications