S-91253A592 5/16"-18 x 2 1/4" 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.
• Black-oxide finish on alloy steel provides enhanced corrosion resistance, extending service life in demanding industrial environments.
• Class 3A thread fit offers superior precision and tighter tolerances for secure, vibration-resistant assemblies.
• Partially threaded design allows for controlled clamping force and easier alignment in specific mounting scenarios.
• Hex drive (3/16") enables high-torque installation with standard tools, speeding up assembly and maintenance processes.
• Flat head with standard profile ensures a flush finish when installed, ideal for applications where protrusion is not acceptable.
• Compliance with ASME B18.3 and ASTM F835 guarantees consistent quality and interoperability in regulated engineering projects.

Professional Applications & Engineering Value

This 5/16"-18 UNC flat head socket cap screw is engineered to address critical challenges in industrial fastening, where high tensile strength and corrosion resistance are paramount. The black-oxide alloy steel construction, combined with a Rockwell C39 hardness, ensures durability against wear and environmental factors, making it suitable for machinery, automotive assemblies, and heavy equipment. The coarse UNC threads and partial threading provide excellent grip in softer materials or where precise thread engagement is needed, reducing the risk of stripping. Its hex drive design allows for efficient installation in confined spaces, enhancing productivity in maintenance and manufacturing lines while meeting rigorous industry standards for safety and performance.

Specification Summary & Compliance

This screw adheres to Class 3A thread fit for precise dimensional accuracy, with specifications including a 5/16"-18 UNC coarse thread, 2-1/4" length, and 82° countersink angle. It complies with ASME B18.3 and ASTM F835 manufacturing standards, ensuring consistent quality. Additionally, it is RoHS 3 (2015/863/EU) compliant and REACH (EC 1907/2006) compliant, supporting environmental and safety regulations in global supply chains.