S-91253A099 3-56 x 1/2" 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 for reliable performance under high-stress applications
• Precise Class 3A thread fit ensures tight, secure fastening with minimal risk of loosening
• Fully threaded design provides maximum grip and uniform load distribution along the entire length
• 82° countersink angle allows for flush mounting, reducing protrusion and improving aesthetics
• Fine UNF threads offer better vibration resistance and finer adjustment capabilities
• Hex drive compatibility enables easy installation with standard tools, reducing assembly time

Professional Applications & Engineering Value

These 3-56 UNF flat head screws are engineered from black-oxide alloy steel to address critical industrial challenges such as vibration-induced loosening and environmental degradation. The Class 3A fine thread fit and fully threaded construction ensure exceptional holding power in precision assemblies like electronics enclosures, automotive components, and machinery frames. The 82° countersink angle facilitates seamless integration into tapered holes, minimizing surface disruption while maintaining structural integrity. With a Rockwell C39 hardness and high tensile rating, these screws deliver long-term reliability in applications demanding corrosion resistance and consistent performance under dynamic loads.

Specification Summary & Compliance

This product adheres to Class 3A thread fit tolerances per UNF standards, with precise dimensions including a 1/2" length and 82° countersink. It meets ASTM F835 specifications for mechanical properties and is compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, ensuring safe and sustainable use in global markets.