S-91257A483 7/16"-20 x 6 1/2" 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 demanding applications
• Superior corrosion resistance provided by zinc yellow-chromate plating, extending service life in harsh environments
• Optimized torque transmission through the external hex drive design, ensuring secure installation and removal
• Precision thread engagement with Class 2A UNF fine threads for vibration resistance and secure fastening
• Enhanced durability from Rockwell C33 hardness, maintaining structural integrity under heavy loads
• Versatile partial threading allowing for both clamping and alignment functions in assembly applications
• Industry-standard compliance with ASME B18.2.1 and SAE J429 specifications, ensuring interchangeability and reliability

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 7/16"-20 UNF fine thread configuration provides superior resistance to vibrational loosening in machinery, construction equipment, and structural assemblies. The zinc yellow-chromate plating creates a protective barrier against corrosion in outdoor or chemically aggressive environments, significantly extending maintenance intervals. With its partial threading design, this fastener offers precise clamping force control while allowing for alignment adjustments in complex assemblies. The external hex drive ensures compatibility with standard tools while providing excellent torque transmission for secure installations in confined spaces. Engineered to meet the rigorous demands of industrial machinery, structural steel connections, and heavy equipment manufacturing, this screw provides reliable performance where high tensile strength and corrosion resistance are paramount.

Specification Summary & Compliance

This Grade 8 hex head screw features precision Class 2A thread fit with 7/16"-20 UNF fine threads and partial threading extending to a minimum of 1-3/8". Manufactured to exacting ASME B18.2.1 and SAE J429 specifications, ensuring dimensional accuracy and mechanical properties. The fastener meets industry standards for heavy-duty applications with verified 150,000 psi tensile strength and Rockwell C33 hardness. The zinc yellow-chromate plating provides corrosion protection while maintaining compliance with industrial finish requirements.