What Is the Difference Between Grade 5 and Grade 8 Bolts? When selecting the right bolt for a project, understanding strength ratings is essential. Grade 5 and Grade 8 bolts are two common choices for construction, automotive, machinery, and industrial applications. Although both are high-strength fasteners, they differ in tensile strength, material properties, and ideal uses. Knowing these differences can help you choose the right product for your application in Houston, TX, USA. What Is a Grade 5 Bolt? A Grade 5 bolt is a medium-to-high-strength fastener commonly made from carbon steel and identified by three radial lines on the head. It typically has a tensile strength of approximately 120,000 psi, making it suitable for many general-purpose mechanical and structural applications. Grade 5 bolts are frequently used when dependable strength is required without the higher strength specifications of Grade 8. They can be found in automotive repairs, machinery, equipment assembly, a...