Bolt and Nut Hardware Identification

For most, its hard to identify the grade or strength of a bolt by looking at it unless you know the labelling.     
Here's the rule of thumb:

  • no markings on the head = Grade 1 or 2.
  • 3 marks = Grade 5
  • 6 marks = Grade 8

For a more complete identification list:
Download the hardware identification chart here