S-91247A552 1/4"-20 x 2 1/2" 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 demanding applications
• Superior corrosion resistance through zinc plating, extending service life in harsh industrial environments
• Optimized torque transmission with external hex drive design for secure installation using standard tools
• Enhanced thread engagement through UNC coarse threading and Class 2A fit, reducing cross-threading risks
• Controlled partial threading providing unthreaded shank for precise clamping in structural assemblies
• Consistent mechanical properties with Rockwell C25 hardness and Grade 5 certification for predictable performance
• Regulatory compliance assurance meeting ASME B18.2.1, RoHS 3, and REACH standards for global industrial use

Professional Applications & Engineering Value

This Grade 5 hex head screw delivers critical engineering solutions where vibration resistance and structural integrity are paramount. The zinc plated steel construction provides essential corrosion protection for outdoor equipment, machinery frames, and construction applications exposed to environmental elements. The 1/4"-20 UNC coarse thread configuration ensures rapid assembly in production environments while maintaining secure fastening in materials where fine threads might strip. The partially threaded design creates a precise bearing surface that prevents joint loosening under dynamic loads, making it ideal for automotive components, industrial machinery, and structural steel connections. With its external hex drive and substantial 2-1/2" length, this fastener accommodates thick material sections while allowing high-torque installation common in maintenance and manufacturing operations.

Specification Summary & Compliance

Manufactured to exacting Class 2A thread fit tolerances with UNC coarse threading (1/4"-20) and minimum 3/4" thread length. Complies with ASME B18.2.1 specifications and SAE J429 Grade 5 requirements, ensuring dimensional consistency and mechanical performance. Meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental compliance standards for use in regulated industries. The inch system measurement provides compatibility with North American equipment and existing industrial specifications.