S-91286A331 1/2"-13 x 2 5/8" ASME B18.2.1, SAE J429 High-Strength Grade 8 Steel Hex Head Screws

Key Features & Benefits at a Glance

• Maximum Load-Bearing Capacity: Grade 8 classification and 150,000 psi tensile strength ensure reliable performance in high-stress industrial applications.
• Superior Corrosion Protection: Zinc-flake coating provides excellent resistance to rust and environmental degradation, extending service life.
• High Durability & Wear Resistance: Rockwell C33 hardness maintains structural integrity under repetitive loading and harsh conditions.
• Easy Installation & Removal: External hex drive and 3/4" head width allow for secure tool engagement and efficient torque application.
• Optimized Thread Engagement: 1/2"-13 UNC coarse threads and Class 2A fit enable quick assembly and reliable fastening in various materials.
• Versatile Partial Threading: Combines strong grip in the threaded section with smooth shank stability for precise clamping applications.
• Industry-Standard Compliance: Manufactured to ASME B18.2.1 and SAE J429 specifications for guaranteed interchangeability and performance.

Professional Applications & Engineering Value

Engineered for demanding industrial environments, this Grade 8 hex head screw delivers critical reliability where failure is not an option. The zinc-flake coated steel construction tackles common corrosion challenges in outdoor machinery, construction equipment, and automotive assemblies, significantly reducing maintenance downtime. Its 1/2"-13 UNC coarse thread and partial threading design provide superior resistance to vibration loosening while allowing precise clamping force distribution. The external hex drive ensures compatibility with standard tools, facilitating quick installation in confined spaces. Ideal for heavy-duty structural connections, industrial machinery frames, and high-vibration equipment, this fastener solves engineering problems related to joint integrity, environmental exposure, and long-term performance requirements.

Specification Summary & Compliance

This 2 5/8" length hex head screw features precise Class 2A thread fit and 1/2"-13 UNC coarse thread specifications per ASME B18.2.1 manufacturing standards. The fastener meets SAE J429 Grade 8 mechanical requirements including 150,000 psi tensile strength and Rockwell C33 hardness. Compliance with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations ensures environmental safety and material restrictions adherence for global industrial applications.