Metric Thread

Class 8.8 metric cap hex bolts have a tensile strength of 800 - 830 N/mm^2 

Class 10.9 metric cap hex bolts have a tensile strength of 1040 N/mm^2 minimum

 

💡 Metric Magic: Decoding the Numbers

Metric Bolt Math Class Rating Reference Rule

The numbers on the head markings tell you the approximate bolt's strength in MPa:

  • First Number × 100 = Tensile Strength
    (e.g., 10.9 → 1,000 MPa)
  • Second Number = Yield Point %
    (e.g., 10.9 → Yield is 90% of Tensile)
  • Math: 1,000 MPa × 0.9 = 900 MPa Yield
Select Class of Steel
Class 10.9
class 10 9 metric cap hex bolts
Class 8.8
class 8 8 metric cap hex bolts