S-91309A603 5/16"-18 x 5" 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
• Easy installation and removal with external hex drive design that provides secure tool engagement and reduces assembly time
• Consistent thread engagement thanks to Class 2A coarse UNC threads that resist loosening from vibration and allow for quick alignment
• Full threading along the 5" length offers maximum grip range and flexibility in material thickness applications
• Durable steel construction with Rockwell B69 hardness maintains structural integrity and withstands repeated use without deformation
• Compliance with major industry standards including ASME B18.2.1 and ASTM A307 guarantees quality and interchangeability

Professional Applications & Engineering Value

These 5/16"-18 UNC hex head screws are engineered to solve critical fastening challenges in industrial settings where vibration resistance, corrosion protection, and high strength are paramount. The zinc plated finish provides an essential barrier against moisture and chemicals, significantly reducing maintenance costs in outdoor or harsh environment applications. With their coarse thread design and Class 2A thread fit, these screws deliver superior holding power in soft materials and prevent cross-threading during installation. The combination of 60,000 psi tensile strength and Rockwell B69 hardness makes them ideal for structural assemblies, machinery frames, and heavy equipment where joint integrity cannot be compromised. Their fully threaded configuration ensures maximum thread contact across various material thicknesses, providing engineers with versatile fastening solutions for construction, manufacturing, and maintenance applications.

Specification Summary & Compliance

This 5/16"-18 UNC hex head screw features precise Class 2A thread fit with coarse thread spacing, manufactured to ASME B18.2.1 specifications and ASTM A307 material standards. The product maintains dimensional accuracy with a 5" length and fully threaded design, ensuring consistent performance across applications. Compliance is verified with RoHS 3 (2015/863/EU) for hazardous substance restrictions and REACH (EC 1907/2006) for chemical safety, meeting the latest regulatory requirements for industrial fasteners in global markets.