S-91247A045 1/4"-28 x 8" ASME B18.2.1, SAE J429 Medium-Strength Grade 5 Steel Hex Head Screws

Key Features & Benefits at a Glance

• Exceptional load-bearing capacity with 120,000 psi tensile strength for reliable performance in high-stress applications
• Superior corrosion resistance through zinc plating, extending service life in demanding industrial environments
• Precise thread engagement with UNF fine threading and Class 2A fit ensuring secure fastening and vibration resistance
• Optimized torque transmission through external hex drive design for efficient installation with standard tools
• Enhanced durability with Rockwell C25 hardness maintaining structural integrity under repeated stress
• Versatile partial threading allowing both clamping and alignment functions in assembly applications
• Regulatory compliance assurance meeting ASME B18.2.1, RoHS 3, and REACH standards for quality and safety

Professional Applications & Engineering Value

This Grade 5 hex head screw delivers critical engineering solutions for industrial assembly challenges where vibration resistance and structural integrity are paramount. The UNF fine threading provides superior thread engagement compared to coarse threads, reducing the risk of loosening in machinery and equipment subjected to constant motion. The zinc plated steel construction offers essential corrosion protection for applications in manufacturing facilities, automotive assembly, and outdoor equipment where environmental exposure is a concern. With partial threading along its 8-inch length, this fastener enables precise clamping force distribution while maintaining alignment in structural frameworks. The external hex drive design ensures compatibility with standard industrial tools, streamlining installation processes in high-volume production environments.

Specification Summary & Compliance

Manufactured to exacting Class 2A thread fit tolerances with UNF fine thread specification (1/4"-28). Complies with ASME B18.2.1 dimensional standards and SAE J429 material requirements for Grade 5 fasteners. Meets RoHS 3 (2015/863/EU) compliance for restricted substances and REACH (EC 1907/2006) regulations for chemical safety. The inch system measurement ensures compatibility with North American industrial specifications and replacement part requirements.