S-91257A213 3/4"-16 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 reliable performance in high-stress applications
• Superior corrosion resistance provided by zinc yellow-chromate plating, extending service life in harsh environments
• Precise thread engagement with Class 2A thread fit ensuring consistent assembly and vibration resistance
• Optimized torque transmission through the 1 1/8" hex head design for secure installation and removal
• Enhanced material durability with Rockwell C33 hardness maintaining structural integrity under repeated loads
• Versatile partial threading allowing for both clamping and alignment functions in various assembly configurations
• Industry-standard compliance meeting ASME B18.2.1 and SAE J429 specifications for guaranteed interoperability

Professional Applications & Engineering Value

This Grade 8 hex head screw delivers critical engineering solutions for heavy machinery, structural assemblies, and industrial equipment where failure is not an option. The 3/4"-16 UNF fine thread configuration provides superior resistance to vibrational loosening while maintaining high clamping forces. The zinc yellow-chromate plating creates a protective barrier against chemical exposure and environmental corrosion, significantly extending maintenance intervals in manufacturing plants, construction sites, and automotive applications. With its partially threaded design, engineers can achieve precise joint compression while the external hex drive enables high-torque installation using standard tools. These steel fasteners are engineered to withstand extreme dynamic loads while maintaining dimensional stability across thermal cycles.

Specification Summary & Compliance

This high-strength hex head screw features precise Class 2A thread fit tolerances with 3/4"-16 UNF fine threading and minimum thread length of 1 3/4". Manufactured to exacting ASME B18.2.1 and SAE J429 specifications, the fastener delivers consistent dimensional accuracy and mechanical properties. The Grade 8 classification guarantees minimum tensile strength of 150,000 psi with Rockwell C33 hardness, while the zinc yellow-chromate finish provides corrosion protection meeting industry standards for industrial applications.