S-91309A578 5/16"-18 x 1/2" ASME B18.2.1, ASTM A307 Low-Strength Steel Hex Head Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with zinc plating for extended service life in demanding environments
• High tensile strength of 60,000 psi ensures reliable performance under heavy loads and vibration
• Rockwell B69 hardness provides excellent durability and resistance to wear and deformation
• External hex drive design allows for easy installation and removal with standard tools
• Coarse UNC threading with Class 2A fit offers quick assembly and secure fastening in various materials
• Full threading along the 1/2" length maximizes grip and load distribution across the entire fastener
• Compliance with ASME B18.2.1 and environmental regulations ensures quality, safety, and environmental responsibility

Professional Applications & Engineering Value

This 5/16"-18 UNC hex head screw delivers exceptional engineering value for industrial assembly and machinery applications. Manufactured from high-strength steel with a zinc-plated finish, it effectively combats corrosion in harsh operating conditions. The coarse thread design and Class 2A thread fit provide rapid installation and reliable holding power in metal, wood, and composite materials, reducing assembly time and improving production efficiency. Its external hex drive ensures compatibility with standard wrenches, making it ideal for maintenance, construction, and heavy equipment where durability and consistent performance are critical.

Specification Summary & Compliance

This screw features a 5/16"-18 UNC coarse thread with Class 2A dimensional accuracy and is fully threaded. It complies with ASME B18.2.1 manufacturing specifications and meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental standards, ensuring regulatory adherence for global industrial use.