S-91257A686 7/16"-14 x 4 1/4" 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 demanding applications
• Superior corrosion resistance provided by zinc yellow-chromate plating, extending service life in harsh environments
• Optimized installation efficiency through external hex drive design that prevents tool slippage and ensures secure fastening
• Enhanced thread engagement with Class 2A thread fit and coarse UNC threading for faster assembly and vibration resistance
• Precise length control with 4 1/4" total length and 1 1/8" minimum thread length for consistent performance across applications
• Industry-standard compliance meeting ASME B18.2.1 and SAE J429 specifications for guaranteed quality and interchangeability
• Durable material construction featuring Grade 8 steel with Rockwell C33 hardness for maximum wear resistance and longevity

Professional Applications & Engineering Value

Engineered for heavy-duty industrial applications, these Grade 8 hex head screws deliver critical performance where structural integrity matters most. The 7/16"-14 UNC coarse threading provides superior resistance to vibration 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 partial threading design, these fasteners optimize clamping force distribution while the external hex drive ensures reliable installation torque transmission without cam-out issues. These screws solve common engineering challenges in heavy machinery, structural steel connections, and industrial equipment where high tensile strength and corrosion protection are paramount requirements.

Specification Summary & Compliance

This hex head screw features precise Class 2A thread fit with 7/16"-14 UNC coarse thread specifications, ensuring proper engagement and interchangeability. Manufacturing complies with ASME B18.2.1 and SAE J429 standards for dimensional accuracy and mechanical properties. The fastener maintains 4 1/4" total length with 1 1/8" minimum thread length and delivers 150,000 psi tensile strength with Rockwell C33 hardness. The zinc yellow-chromate plating provides corrosion protection while meeting industry requirements for surface treatment durability.