S-91309A591 5/16"-18 x 2" ASME B18.2.1, ASTM A307 Low-Strength Steel Hex Head Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with zinc plating that protects against rust and extends service life in demanding environments
• High tensile strength of 60,000 psi ensures reliable performance and load-bearing capacity for heavy-duty applications
• Precise Class 2A thread fit provides smooth assembly and secure fastening with reduced risk of cross-threading
• Full threading along the 2" length offers maximum grip and adjustment flexibility in various material thicknesses
• External hex drive design allows for easy installation and high torque application with standard tools
• Coarse UNC thread pattern enables quick assembly and superior resistance to vibration loosening
• Industry compliance with ASME B18.2.1 and ASTM A307 standards guarantees consistent quality and dimensional accuracy

Professional Applications & Engineering Value

This 5/16"-18 UNC hex head screw delivers exceptional engineering value through its steel construction and zinc plating, specifically designed to address common industrial challenges. The combination of 60,000 psi tensile strength and Rockwell B69 hardness ensures reliable performance in structural applications, machinery assembly, and heavy equipment where vibration resistance is critical. The coarse thread design provides superior holding power in softer materials and faster installation times, while the external hex drive accommodates high torque requirements without stripping. These fully threaded fasteners are ideal for construction, manufacturing, and maintenance applications where consistent clamping force and corrosion protection are essential for long-term reliability.

Specification Summary & Compliance

This hex head screw features Class 2A thread fit tolerance for precise engagement and meets ASME B18.2.1 dimensional specifications under ASTM A307 material standards. The product maintains compliance with RoHS 3 (2015/863/EU) for restricted substances and REACH (EC 1907/2006) regulations, ensuring environmental responsibility. Manufacturing follows inch system measurements with UNC coarse threads, right-hand thread direction, and full threading along the 2" length for consistent performance across industrial applications.