S-91309A589 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, extending service life in harsh industrial environments
• High tensile strength of 60,000 psi ensures reliable load-bearing capacity for demanding applications
• Rockwell B69 hardness provides excellent durability and resistance to wear and deformation
• Coarse UNC threads offer faster installation and reduced risk of cross-threading in assembly operations
• External hex drive design allows for easy tightening with standard tools, improving installation efficiency
• Full threading along the 1 3/4" length ensures maximum grip and uniform stress distribution
• Compliance with ASME B18.2.1 and ASTM A307 guarantees consistent quality and interchangeability

Professional Applications & Engineering Value

This 5/16"-18 UNC hex head screw is engineered from high-strength steel to address critical challenges in industrial fastening, such as vibration loosening and structural fatigue. The coarse thread design and Class 2A thread fit provide rapid assembly in materials like cast iron or soft metals, reducing installation time while maintaining secure connections. With a zinc-plated finish, it resists corrosion in outdoor or humid settings, making it ideal for machinery, construction, and automotive applications. Its fully threaded configuration ensures even load distribution, minimizing stress concentrations and enhancing joint integrity in heavy-duty frameworks.

Specification Summary & Compliance

This fastener features a 5/16"-18 UNC coarse thread with Class 2A tolerance for precise fit and interchangeability. Manufactured in compliance with ASME B18.2.1 and ASTM A307 specifications, it assures dimensional accuracy and mechanical performance. Additionally, it meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, supporting safe and sustainable usage in global supply chains.