S-91286A165 5/16"-18 x 2 1/4" 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 applications.
• Superior Corrosion Protection: Zinc-flake coating provides excellent resistance to rust and environmental degradation, extending service life.
• Optimized Thread Engagement: UNC coarse threads and Class 2A fit enable faster installation and secure fastening in various materials.
• Enhanced Durability: Rockwell C33 hardness offers exceptional wear resistance and maintains integrity under repetitive loads.
• Secure Drive System: External hex head design allows for high-torque application with standard tools, preventing stripping.
• Versatile Partial Threading: Combines strong thread grip with an unthreaded shank for improved shear strength in structural connections.
• Regulatory Compliance: Meets ASME B18.2.1 and SAE J429 standards, ensuring consistent quality and interchangeability.

Professional Applications & Engineering Value

This Grade 8 hex head screw is engineered for demanding environments where failure is not an option. The zinc-flake coated steel construction addresses critical corrosion challenges in outdoor, automotive, and heavy machinery applications, significantly reducing maintenance cycles. The 5/16"-18 UNC coarse thread provides superior pull-out resistance in brittle materials and allows for quicker assembly compared to fine-thread alternatives. With a 150,000 psi tensile strength and partial threading, it delivers optimal clamp load distribution while resisting vibrational loosening in structural frameworks, construction assemblies, and industrial equipment. These screws are specifically designed to meet the rigorous demands of OEM manufacturing and MRO operations where high-strength fasteners are essential for operational safety and longevity.

Specification Summary & Compliance

This fastener features Class 2A thread fit per ASME B18.2.1 specifications, ensuring precise dimensional accuracy and interchangeability. Manufacturing complies with SAE J429 Grade 8 mechanical properties, including hardness (Rockwell C33) and tensile strength (150,000 psi) requirements. The product is fully RoHS 3 (2015/863/EU) Compliant and REACH (EC 1907/2006) Compliant, meeting the latest environmental and safety regulations for industrial components.