S-91257A920 7/8"-9 x 4 3/4" 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 150,000 psi tensile strength for critical structural applications
• Superior corrosion resistance through zinc yellow-chromate plating in demanding environments
• Optimized torque transmission via external hex drive design for secure installation
• Enhanced durability with Rockwell C33 hardness maintaining performance under stress
• Reliable thread engagement with Class 2A fit ensuring consistent assembly quality
• Versatile partial threading allowing flexibility in clamp load distribution
• Industry-standard compliance meeting ASME B18.2.1 and SAE J429 specifications

Professional Applications & Engineering Value

Engineered for heavy-duty industrial applications, these Grade 8 hex head screws deliver critical performance where structural integrity is paramount. The 7/8"-9 UNC coarse thread configuration provides superior resistance to vibration loosening in machinery, construction equipment, and transportation systems. The zinc yellow-chromate plating creates a protective barrier against corrosion in harsh operating conditions, while the partial threading design allows precise clamp load control. With 150,000 psi tensile strength and Rockwell C33 hardness, these fasteners maintain dimensional stability under extreme loads, making them ideal for high-stress connections in manufacturing, infrastructure, and heavy equipment assembly.

Specification Summary & Compliance

This 4 3/4" length hex head screw features Class 2A thread fit per UNC standards with 2" minimum thread length. Manufactured to ASME B18.2.1 dimensional specifications and SAE J429 Grade 8 mechanical properties. The inch system fastener demonstrates precision threading with coarse thread spacing for optimal performance in industrial applications requiring high-strength fasteners with reliable compliance to established engineering standards.