S-91253A078 2-56 x 5/16" ASTM F835 Alloy Steel Hex Drive Flat Head Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with black-oxide coating, extending service life in demanding industrial environments
• Exceptional mechanical strength with 130,000 psi tensile strength and Rockwell C39 hardness for reliable performance under high stress
• Precision thread engagement with Class 3A fit and UNC coarse threads ensuring secure fastening and vibration resistance
• Optimal flush mounting with standard 82° countersink angle and flat head design for seamless surface integration
• Efficient installation through hex drive (0.050") design providing superior torque transmission and slip resistance
• Full threading coverage across the 5/16" length for maximum grip and load distribution
• Regulatory compliance assurance meeting ASTM F835, RoHS 3, and REACH standards for global industrial applications

Professional Applications & Engineering Value

These black-oxide alloy steel flat head screws deliver critical performance advantages in precision assembly applications where surface flushness and high tensile strength are paramount. The UNC coarse thread configuration with Class 3A thread fit provides excellent engagement in various materials while resisting vibration-induced loosening. The 82° countersink angle ensures proper seating in standard chamfered holes, preventing protrusion in sensitive equipment. Engineered with fully threaded design and hex drive compatibility, these fasteners offer superior installation control in confined spaces common in electronics enclosures, machinery guards, and automotive components. The combination of 130,000 psi tensile strength and corrosion-resistant black-oxide finish makes them ideal for applications demanding both mechanical reliability and environmental durability.

Specification Summary & Compliance

Manufactured to precise dimensional standards with Class 3A thread fit tolerance and UNC coarse thread profile (2-56 specification). The 5/16" length and 0.197" head diameter maintain consistent dimensional accuracy. Compliance with ASTM F835 manufacturing specifications ensures material and performance reliability. Environmental compliance verified through RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) certifications, confirming restricted substance adherence for global industrial distribution.