S-91257A605 5/16"-18 x 7" ASME B18.2.1, SAE J429 High-Strength Grade 8 Steel Hex Head Screws

Key Features & Benefits at a Glance

• Maximum Load-Bearing Capacity - Grade 8 classification and 150,000 psi tensile strength ensure reliable performance in high-stress industrial environments
• Superior Corrosion Protection - Zinc yellow-chromate plating provides enhanced resistance to rust and environmental degradation
• Optimized Thread Engagement - UNC coarse threading with Class 2A fit guarantees secure fastening and vibration resistance
• Enhanced Installation Efficiency - External hex drive design allows for quick assembly with standard tools while preventing stripping
• Precision Engineering - Partially threaded configuration provides both gripping strength and clearance where needed
• Industry Compliance - Meets ASME B18.2.1 and SAE J429 standards for consistent quality and interchangeability
• Durable Material Construction - Steel composition with Rockwell C33 hardness delivers long-term reliability under heavy loads

Professional Applications & Engineering Value

Engineered for demanding industrial and construction applications, these Grade 8 hex head screws address critical fastening challenges where failure is not an option. The 5/16"-18 UNC coarse thread configuration provides superior holding power in various materials, while the partially threaded design allows for precise clamp load distribution. The zinc yellow-chromate plating significantly extends service life in corrosive environments, making these heavy-duty fasteners ideal for structural steel connections, machinery assembly, and infrastructure projects. With 7-inch length and external hex drive, installation becomes efficient even in confined spaces, reducing labor time while maintaining the integrity of critical connections.

Specification Summary & Compliance

This inch system fastener features precise Class 2A thread fit tolerances ensuring consistent engagement and reliability. Manufactured to ASME B18.2.1 specifications and compliant with SAE J429 Grade 8 standards, the screw delivers guaranteed mechanical properties including 150,000 psi tensile strength and Rockwell C33 hardness. The partially threaded configuration with 1 1/8" minimum thread length provides optimal performance characteristics for heavy-duty applications requiring both strength and precision.