S-91257A453 5/16"-24 x 7" ASME B18.2.1, SAE J429 High-Strength Grade 8 Steel Hex Head Screws

Key Features & Benefits at a Glance

• Exceptional load-bearing capability with Grade 8 classification and 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 demanding industrial environments
• Precise thread engagement with UNF fine threading and Class 2A fit ensuring secure fastening and vibration resistance
• Optimized torque transmission through external hex drive design and standard hex head for efficient installation with common tools
• Enhanced durability from Rockwell C33 hardness, maintaining structural integrity under repeated stress cycles
• Versatile partial threading allowing both threaded engagement and smooth shank functionality in assembly applications
• Industry-standard compliance with ASME B18.2.1 and SAE J429 specifications, guaranteeing interchangeability and quality assurance

Professional Applications & Engineering Value

These Grade 8 hex head screws deliver critical engineering solutions for heavy machinery, structural assemblies, and industrial equipment where high tensile strength and corrosion resistance are paramount. The 5/16"-24 UNF fine threading provides superior vibration resistance compared to coarse threads, while the zinc yellow-chromate plating creates a protective barrier against environmental degradation. The partially threaded design offers dual functionality: the threaded portion ensures secure fastening while the smooth shank resists shear forces. With 7-inch length and external hex drive, these fasteners are engineered for accessibility in confined spaces and compatibility with standard wrenching tools, making them ideal for construction, automotive, and manufacturing applications requiring heavy-duty performance and long-term reliability.

Specification Summary & Compliance

Manufactured to precise Class 2A thread fit tolerances with 5/16"-24 UNF fine threading and right-hand thread direction. These steel fasteners meet rigorous ASME B18.2.1 and SAE J429 specifications for dimensional accuracy and mechanical properties. The zinc yellow-chromate plating provides corrosion protection while maintaining compliance with industrial standards. With Rockwell C33 hardness and 150,000 psi tensile strength, these hex head screws deliver consistent performance in demanding applications where quality and reliability are non-negotiable.