S-91253A870 5/8"-18 x 1 1/2" ASTM F835 Alloy Steel Hex Drive Flat Head Screws

Key Features & Benefits at a Glance

• Exceptional tensile strength of 130,000 psi ensures reliable performance in high-stress applications, reducing the risk of fastener failure.
• Corrosion-resistant black-oxide finish on alloy steel enhances durability and provides protection in demanding industrial environments.
• Class 3A fine threading offers superior thread engagement and vibration resistance, maintaining secure connections over time.
• Fully threaded design allows for maximum grip along the entire length, improving load distribution and fastening stability.
• 82° countersink angle enables a flush fit in standard countersunk holes, minimizing protrusion and creating a smooth surface.
• Hex drive (3/8") facilitates easy installation and removal with common tools, reducing assembly time and effort.
• Compliance with ASTM F835, RoHS 3, and REACH ensures adherence to industry standards and environmental regulations for safe, global use.

Professional Applications & Engineering Value

This 5/8"-18 UNF flat head socket cap screw is engineered to address critical fastening challenges in industrial settings. The black-oxide alloy steel construction, combined with a Rockwell C37 hardness, provides excellent wear resistance and longevity, making it ideal for machinery, automotive assemblies, and structural applications where vibration and dynamic loads are common. The fine UNF thread and Class 3A fit ensure precise alignment and tight sealing, reducing the likelihood of loosening under stress. Its fully threaded body and 82° countersink allow for seamless integration into components, offering a reliable solution for engineers seeking durability, compliance, and ease of maintenance in high-performance fastening systems.

Specification Summary & Compliance

This screw features a 5/8"-18 UNF thread with Class 3A tolerance for high precision and fine thread spacing. It meets ASTM F835 specifications for mechanical properties and is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring environmental safety and suitability for industrial use.