S-91253A083 2-56 x 5/8" ASTM F835 Alloy Steel Hex Drive Flat Head Screws

Key Features & Benefits at a Glance

• Exceptional durability with 130,000 psi tensile strength and Rockwell C39 hardness for reliable performance in demanding industrial environments
• Precise Class 3A thread fit ensures secure, vibration-resistant fastening and consistent assembly quality
• Black-oxide coating on alloy steel provides superior corrosion resistance and extended service life
• 82° countersink angle allows for flush mounting, reducing protrusion and improving aesthetic finish
• Hex drive design offers easy installation with standard tools, minimizing assembly time and labor costs
• Fully threaded shank maximizes grip length and load distribution across the entire fastener
• Compliance with ASTM F835, RoHS, and REACH guarantees material consistency and environmental safety for global supply chains

Professional Applications & Engineering Value

These 2-56 UNC flat head screws are engineered to address critical challenges in precision assembly and high-stress applications. The black-oxide alloy steel construction combined with Class 3A thread fit ensures minimal backlash and superior resistance to loosening under dynamic loads. Ideal for machinery, electronics, and automotive components, the 82° countersink angle and flat head profile provide a seamless finish while the hex drive facilitates quick, tool-friendly installation. With coarse thread spacing and fully threaded design, these screws deliver enhanced holding power in brittle materials or thin-section assemblies, reducing the risk of strip-out and improving long-term reliability in industrial screw applications.

Specification Summary & Compliance

This product meets Class 3A thread tolerance per UNC standards with a right-hand thread direction and coarse thread spacing. Manufacturing and material specifications conform to ASTM F835, ensuring consistent mechanical properties. The screws are fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, confirming adherence to environmental and safety standards for industrial use.