Resources, Tip and Information

Bolt Heads

Bolt Heads

We are curious about what makes each bolt unique. We want to help you become more knowledgeable about bolts, threads & fasteners! Each bolt has its own special markings to make it easy to identify.

For instance, did you know that bolt heads have different identifications?

  • 3 lines- Gr. 5 bolts
  • 6 lines-Gr. 8 bolts
  • 10.9- metric bolts (equivalent to Gr. 8 bolts) 
  • 8.8- metric bolts (equivalent to Gr. 5 bolts) 
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