How to calculate the bolt tightening torque using the table above as follows:
There are 2 types of screws, Allen screws and hexagon screws, each of which has a grade.
Each screw has an inner size (Hex) as shown below:
Example of a Screw
Example, M24 size hexagon screws with Grade 12.9 can be seen in the table:
From the table it can be seen the units needed for M24 size screws with Grade 12.9 of 1196 Nm or 883 lbf ft.