S-91286A266 3/8"-24 x 4" ASME B18.2.1, SAE J429 High-Strength Grade 8 Steel Hex Head Screws

Key Features & Benefits at a Glance

• Exceptional load-bearing capacity with Grade 8 classification and 150,000 psi tensile strength for reliable performance in high-stress applications
• Superior corrosion protection through zinc-flake coating, extending service life in harsh industrial environments
• Precise thread engagement with Class 2A fit and UNF fine threads ensuring vibration resistance and secure fastening
• Optimized torque transmission via external hex drive and 9/16" head width for easy installation with standard tools
• Controlled thread engagement through partial threading design preventing over-tightening in deep applications
• Consistent hardness performance with Rockwell C33 rating maintaining structural integrity under repeated loads
• Regulatory compliance assurance meeting ASME, SAE, RoHS 3 and REACH standards for global industrial use

Professional Applications & Engineering Value

Engineered for demanding industrial applications, these Grade 8 hex head screws deliver exceptional performance where failure is not an option. The zinc-flake coated steel construction provides superior corrosion resistance in manufacturing environments exposed to chemicals, moisture, and temperature variations. The 3/8"-24 UNF fine thread configuration offers enhanced clamping force distribution and superior vibration resistance compared to coarse threads, making these partially threaded fasteners ideal for machinery assembly, structural frameworks, and heavy equipment where precise thread engagement is critical. The external hex drive design ensures maximum torque application without stripping, while the 4" length accommodates thick material sections commonly found in industrial construction and manufacturing applications.

Specification Summary & Compliance

This hex head screw features precise Class 2A thread fit tolerance per UNF standards with 3/8"-24 thread size and 1" minimum thread length. Manufacturing complies with ASME B18.2.1 and SAE J429 Grade 8 specifications, ensuring dimensional accuracy and mechanical properties. The fastener meets RoHS 3 (2015/863/EU) compliance for hazardous substance restrictions and REACH (EC 1907/2006) regulations for chemical safety, making it suitable for international industrial markets requiring stringent environmental compliance.