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BOLT & NUT TIGHTENING TORQUE
Standard bolt & nut tightening torque
Tightening torques of standard bolts and nuts are not indicated throughout the manual.
Use the charts and table below to judge the standard tightening torque.
1. Judge the tightening torque for the hexagon head bolt, welded bolt or stud bolt having the standard
bearing surface according to the tightening torque table by identifying the bolt strength class from the
table below.
2. Judge the tightening torque for the hexagon flange bolt based on the threading diameter.
3. The nut tightening torque can be judged from its corresponding bolt type.
BOLT STRENGTH CLASS IDENTIFICATION METHOD AND TIGHTENING TORQUE
Identification by actual part
Type
Shape and class
Class
Hexagon head bolt
(standard)
Number in relief or hallmark on the head
4 = 4T
5 = 5T
6 = 6T
7 = 7T
8 = 8T
No mark
4T
Bolt with two raised lines on head
5T
Bolt with three raised lines on head
7T
Bolt with four raised lines on head
8T
Welded bolt
4T
Stud bolt
No mark
4T
2 mm groove(s) on one/both edge(s)
6T
