S-91286A166 5/16"-18 x 2 1/2" 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 Grade 8 classification and 150,000 psi tensile strength for reliable performance in high-stress applications.
• Superior corrosion resistance provided by zinc-flake coating, ensuring long-term durability in harsh industrial environments.
• Optimized thread engagement with UNC coarse threads and Class 2A fit for faster assembly and reduced cross-threading risks.
• High hardness rating of Rockwell C33 minimizes wear and deformation under repeated use.
• Secure external hex drive allows for high-torque installation with standard tools, preventing stripping.
• Versatile partial threading design offers both gripping strength and clearance where needed.
• Compliance with major standards including ASME B18.2.1 and SAE J429, ensuring interchangeability and quality.

Professional Applications & Engineering Value

Engineered for heavy-duty industrial applications, this Grade 8 hex head screw addresses critical needs in machinery, construction, and automotive assemblies where vibration and high tensile loads are common. The zinc-flake coated steel construction provides a robust barrier against corrosion, significantly extending service life in outdoor or chemically aggressive settings. With its 5/16"-18 UNC coarse thread and partial threading, it ensures rapid installation and secure clamping force, reducing assembly time while maintaining joint integrity. The external hex drive facilitates easy access in confined spaces, making it a preferred choice for maintenance and OEM applications requiring dependable, high-strength fastening solutions.

Specification Summary & Compliance

This screw adheres to Class 2A thread fit tolerances and is manufactured in accordance with ASME B18.2.1 and SAE J429 standards. It is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring environmental safety and material sustainability.