S-91253A116 4-40 x 9/16" ASTM F835 Alloy Steel Hex Drive Flat Head Screws

Key Features & Benefits at a Glance

• Enhanced corrosion resistance with black-oxide coating, ideal for harsh industrial environments.
• Superior tensile strength of 130,000 psi ensures reliable, high-load fastening without failure.
• Precise Class 3A thread fit provides consistent engagement and vibration resistance in assemblies.
• Fully threaded design maximizes grip and distribution of clamping force along the entire length.
• Standard 82° countersink angle allows for flush mounting, reducing protrusion and improving aesthetics.
• Hex drive (1/16") enables easy installation and high torque application with common tools.
• Compliance with ASTM F835, RoHS 3, and REACH guarantees material safety and regulatory adherence for global use.

Professional Applications & Engineering Value

Engineered for demanding industrial applications, these 4-40 UNC flat head screws in black-oxide alloy steel address critical needs for durability and reliability. The coarse thread spacing and Class 3A thread fit ensure quick assembly and secure fastening in materials prone to vibration loosening, such as machinery and electronic enclosures. With a Rockwell C39 hardness and fully threaded body, they resist wear and provide uniform stress distribution, reducing the risk of strip-out under dynamic loads. The hex drive facilitates efficient installation in confined spaces, making them ideal for corrosion-resistant fastening in automotive, aerospace, and heavy equipment sectors where consistent performance is paramount.

Specification Summary & Compliance

This screw adheres to Class 3A thread tolerances for precise fit, with UNC coarse threads and right-hand thread direction. 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 for professional use.