S-91236A589 5/16"-18 x 1 3/4" 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 under heavy loads and prevents fastener failure
• Rockwell B69 hardness provides excellent durability and resistance to wear during installation and use
• Class 2A thread fit offers consistent, reliable engagement for easier assembly and reduced cross-threading risks
• External hex drive design allows for high-torque installation with standard tools, speeding up assembly processes
• Partial threading provides unthreaded shank for precise clamping and improved shear strength in structural applications
• Coarse UNC thread pattern enables faster installation and better performance in materials prone to stripping

Professional Applications & Engineering Value

These 5/16"-18 UNC hex head screws deliver exceptional engineering value for industrial applications requiring reliable fastening solutions. The steel construction with zinc plating addresses common corrosion concerns in manufacturing, construction, and machinery applications, while the partial threading design provides optimal clamping force distribution. The coarse thread pattern ensures secure fastening in softer materials and allows for quicker assembly in production environments. With external hex drive compatibility, these screws enable high-torque installation using standard industrial tools, reducing assembly time and labor costs. The combination of 60,000 psi tensile strength and proper thread engagement makes them ideal for structural connections, equipment assembly, and heavy-duty applications where vibration resistance and long-term reliability are critical.

Specification Summary & Compliance

This hex head screw features precise Class 2A thread fit per UNC standards with 5/16"-18 coarse threading and 1 3/4" length. Manufactured to meet ASME B18.2.1 specifications with ASTM A307 material standards, ensuring dimensional accuracy and performance consistency. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, making it suitable for use in regulated industries and international markets.