S-91257A858 3/4"-10 x 5 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 demanding industrial applications
• Superior corrosion resistance provided by zinc yellow-chromate plating, extending service life in harsh environments
• Optimal hardness and durability with Rockwell C33 rating, ensuring minimal wear and deformation under heavy loads
• Easy installation and removal through external hex drive design combined with UNC coarse threading for efficient assembly
• Precise thread engagement with Class 2A thread fit, delivering consistent fastening performance and vibration resistance
• 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 quality and interchangeability

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 combination of 150,000 psi tensile strength and Rockwell C33 hardness provides exceptional resistance to shock loads and fatigue, while the zinc yellow-chromate plating offers superior protection against corrosion in challenging environments. The UNC coarse thread design ensures rapid installation and reliable performance in vibration-prone applications, and the partial threading allows for precise clamping force distribution. These steel fasteners are engineered to maintain integrity in construction, manufacturing, and heavy equipment applications where external hex drive accessibility and high-strength requirements are paramount.

Specification Summary & Compliance

This heavy-duty hex head screw features precise Class 2A thread fit tolerances with 3/4"-10 UNC coarse spacing threads and 5 3/4" length in the inch measurement system. Manufactured to exacting ASME B18.2.1 and SAE J429 standards, ensuring dimensional consistency and mechanical properties. The fastener meets industry specifications for Grade 8 strength classification with verified 150,000 psi tensile strength and Rockwell C33 hardness, providing assurance of performance in critical applications.