S-91253A805 5/8"-11 x 2 3/4" 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 under high-stress conditions, reducing the risk of fastener failure in demanding applications.
• Superior corrosion resistance from the black-oxide finish on alloy steel extends service life and maintains integrity in harsh industrial environments.
• Precise Class 3A thread fit provides tighter tolerances for secure, vibration-resistant connections, minimizing loosening in machinery and equipment.
• Fully threaded UNC coarse design allows for faster installation and stronger holding power in a wide range of materials, boosting assembly efficiency.
• 82° countersink angle and flat head enable flush mounting for a smooth, professional finish, preventing snagging and improving safety.
• Hex drive compatibility (3/8") offers easy installation with common tools, reducing labor time and ensuring consistent torque application.
• Compliance with ASTM F835, RoHS 3, and REACH guarantees adherence to industry standards for safety, environmental responsibility, and material quality.

Professional Applications & Engineering Value

Engineered for heavy-duty industrial use, these 5/8"-11 UNC flat head screws in black-oxide alloy steel address common challenges like vibration-induced loosening and corrosion in machinery, construction, and automotive assemblies. The coarse thread and Class 3A fit ensure rapid, secure fastening in metals and composites, while the 82° countersink provides a seamless fit that reduces stress concentrations. With a Rockwell C37 hardness and high tensile strength, they withstand extreme loads and repetitive use, making them ideal for structural applications where durability and reliability are critical. This combination of material properties and precise threading minimizes maintenance needs and enhances long-term performance in demanding environments.

Specification Summary & Compliance

This product features a 5/8"-11 UNC coarse thread with Class 3A thread fit for high precision, fully threaded right-hand design, and dimensions including a 2 3/4" length and 1.188" head diameter. It meets ASTM F835 specifications for mechanical properties and is compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring environmental safety and material integrity.