S-91253A722 1/2"-13 x 2 1/2" ASTM F835 Alloy Steel Hex Drive Flat Head Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with black-oxide coating on alloy steel, extending service life in demanding industrial environments.
• Exceptional tensile strength of 130,000 psi ensures reliable performance under high-stress conditions, reducing fastener failure risks.
• Precision Class 3A thread fit provides consistent engagement and vibration resistance, minimizing loosening in critical assemblies.
• Optimized 82° countersink angle allows for flush mounting, improving aesthetics and reducing snag hazards in machinery.
• Hex drive design (5/16") enables high-torque installation with standard tools, speeding up assembly and maintenance workflows.
• Coarse UNC threading facilitates quick alignment and installation, especially in softer materials or field repairs.
• Compliance with ASME B18.3 and ASTM F835 guarantees dimensional accuracy and material consistency for quality assurance.

Professional Applications & Engineering Value

These 1/2"-13 UNC flat head screws are engineered to address common industrial challenges such as vibration-induced loosening and corrosion in heavy machinery. The black-oxide alloy steel construction, combined with a Rockwell C39 hardness, provides durability against wear and environmental exposure, making them ideal for construction equipment, automotive frames, and industrial assembly lines. The partially threaded design ensures secure clamping in pre-tapped holes or through-materials, while the hex drive allows for efficient installation in confined spaces. By meeting ASME B18.3 standards, these screws deliver reliable performance in high-load applications, reducing maintenance downtime and enhancing operational safety.

Specification Summary & Compliance

This product adheres to Class 3A thread fit for precise UNC coarse threading, with a minimum thread length of 1-3/8" and overall length of 2-1/2". It complies with ASME B18.3 and ASTM F835 specifications for dimensional accuracy and material properties. Additionally, it is RoHS 3 (2015/863/EU) Compliant and REACH (EC 1907/2006) Compliant, ensuring environmental safety and regulatory adherence in global supply chains.