S-91255A593 5/16"-18 x 7/16" ASTM F835 Steel Button Head Hex-Drive Screws

Key Features & Benefits at a Glance

• Exceptional tensile strength of 120,000 psi ensures reliable performance under high-stress conditions, reducing the risk of fastener failure in demanding applications.
• Class 3A thread fit provides tighter tolerances for superior engagement and vibration resistance, minimizing loosening in machinery and equipment.
• Black-oxide coating on alloy steel offers enhanced corrosion resistance and a durable finish, extending service life in harsh industrial environments.
• Hex drive design with 3/16" drive size allows for easy installation and high torque application, speeding up assembly and maintenance processes.
• Fully threaded coarse UNC pattern ensures quick and secure fastening, ideal for applications requiring strong holding power and ease of use.
• Rounded button head profile reduces surface protrusion and provides a smooth, low-profile finish, enhancing safety and aesthetics in assembled products.
• Compliance with ASME B18.3 and ASTM F835 standards guarantees consistent quality and interoperability, supporting reliable sourcing for engineering projects.

Professional Applications & Engineering Value

This 5/16"-18 UNC rounded head hex screw is engineered to address common industrial challenges, such as vibration-induced loosening and corrosion in heavy-duty assemblies. Constructed from black-oxide alloy steel with a Rockwell C39 hardness, it delivers robust durability and resistance to wear, making it suitable for machinery, automotive, and construction applications. The coarse thread and Class 3A fit ensure precise, secure fastening in materials where fine threads might strip, while the hex drive facilitates efficient installation with standard tools. By meeting rigorous standards like ASME B18.3, it provides engineers with a reliable component that minimizes downtime and maintenance costs in high-stress environments.

Specification Summary & Compliance

This screw features a 5/16"-18 UNC thread with a Class 3A fit for high precision, fully threaded coarse spacing, and right-hand direction. It complies with ASME B18.3 and ASTM F835 specifications, ensuring dimensional accuracy and performance reliability. Additionally, it is RoHS 3 (2015/863/EU) Compliant and REACH (EC 1907/2006) Compliant, supporting environmentally responsible and safe use in global industrial supply chains.