S-91257A648 3/8"-16 x 6" 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 150,000 psi tensile strength for reliable performance in high-stress applications
• Superior corrosion resistance through zinc yellow-chromate plating that protects against harsh industrial environments
• Optimized torque transmission with external hex drive design for secure installation and removal
• Enhanced thread engagement through Class 2A thread fit ensuring precise assembly and vibration resistance
• Reduced weight and material usage with partial threading while maintaining full structural integrity
• Maximum durability with Rockwell C33 hardness that withstands wear and deformation under heavy loads
• Industry-standard compatibility with UNC coarse threads for quick installation in various materials

Professional Applications & Engineering Value

This Grade 8 hex head screw delivers critical engineering solutions for heavy-duty industrial applications where failure is not an option. The 3/8"-16 UNC coarse thread configuration provides excellent pull-out resistance in steel frameworks, machinery assembly, and structural supports. The zinc yellow-chromate plating creates a protective barrier against corrosion in manufacturing facilities, outdoor equipment, and automotive applications. With partial threading, engineers achieve optimal clamp load distribution while reducing stress concentration points. The external hex drive design ensures maximum torque application during installation, preventing stripping and maintaining joint integrity in high-vibration environments. These steel fasteners are engineered to maintain their 150,000 psi tensile strength under extreme conditions, making them ideal for critical connections in construction, transportation, and heavy machinery where reliability is paramount.

Specification Summary & Compliance

This 6" length hex head screw features precise Class 2A thread fit with 3/8"-16 UNC coarse thread specifications and 1" minimum thread length. Manufactured to meet ASME B18.2.1 and SAE J429 Grade 8 standards, ensuring dimensional accuracy and performance reliability. The fastener is fully compliant with RoHS 3 (2015/863/EU) regulations and REACH (EC 1907/2006) requirements, confirming environmental safety and chemical substance restrictions adherence for global industrial use.