S-91286A169 5/16"-18 x 2 3/4" ASME B18.2.1, SAE J429 High-Strength Grade 8 Steel Hex Head Screws

Key Features & Benefits at a Glance

• Exceptional tensile strength of 150,000 psi ensures reliable performance in high-stress industrial applications, reducing failure risks.
• Superior corrosion resistance with zinc-flake coating extends service life in harsh environments, minimizing maintenance needs.
• High hardness (Rockwell C33) provides excellent wear resistance, maintaining thread integrity through repeated use.
• Coarse UNC threads offer faster installation and better debris clearance, improving assembly efficiency.
• Class 2A thread fit ensures consistent, secure fastening with standard nuts, enhancing joint reliability.
• Partially threaded design allows for precise clamping force control, preventing over-tightening in critical assemblies.
• External hex drive enables high-torque application with common tools, speeding up maintenance and repairs.

Professional Applications & Engineering Value

Engineered for demanding industrial applications, this Grade 8 hex head screw combines high-strength steel with a zinc-flake coating to address common challenges like vibration loosening and environmental degradation. The coarse UNC thread design facilitates quick assembly in structural frameworks, machinery, and automotive components, while the partially threaded shank ensures optimal stress distribution. Its 150,000 psi tensile strength and Rockwell C33 hardness make it ideal for heavy-duty fastening where durability and corrosion resistance are critical, reducing downtime and replacement costs in right-hand thread systems.

Specification Summary & Compliance

This fastener adheres to Class 2A thread fit tolerances and UNC coarse thread standards, manufactured in compliance with ASME B18.2.1 and SAE J429 specifications. It is fully RoHS 3 (2015/863/EU) Compliant and REACH (EC 1907/2006) Compliant, ensuring environmental safety and regulatory alignment for global industrial use.