S-91253A114 4-40 x 7/8" ASTM F835 Alloy Steel Hex Drive Flat Head Screws

Key Features & Benefits at a Glance

• Exceptional durability with Black-Oxide Alloy Steel construction providing superior corrosion resistance and longevity in harsh industrial environments
• Maximum load-bearing capacity thanks to 130,000 psi tensile strength and Rockwell C39 hardness for reliable performance under high-stress conditions
• Precision installation and removal with 1/16" hex drive design ensuring secure tool engagement and reduced stripping risk
• Superior thread engagement through Class 3A thread fit and UNC coarse threading for enhanced vibration resistance and secure fastening
• Optimal flush mounting with 82° countersink angle and standard flat head profile for seamless surface integration
• Full-length fastening capability with 7/8" fully threaded design providing maximum grip range and holding power
• Regulatory compliance assurance meeting ASTM F835, RoHS 3, and REACH standards for quality and environmental safety

Professional Applications & Engineering Value

These 4-40 UNC flat head screws deliver critical engineering solutions for industrial applications requiring precision and reliability. The Black-Oxide Alloy Steel construction provides essential corrosion protection while maintaining the 130,000 psi tensile strength needed for high-stress assemblies. The Class 3A thread fit ensures tight tolerances and superior vibration resistance in machinery, electronic enclosures, and precision equipment. The 82° countersink angle allows for perfect flush mounting in metal fabrication and aerospace components, while the fully threaded 7/8" length offers maximum adjustment flexibility. Engineered to solve common industrial challenges including fastener loosening, material fatigue, and environmental degradation, these hex drive screws provide dependable performance in demanding applications where precision and durability are paramount.

Specification Summary & Compliance

Manufactured to exacting standards with Class 3A thread fit precision and UNC coarse thread spacing for optimal performance. These flat head screws feature a standard 82° countersink angle and right-hand thread direction with complete threading along the 7/8" length. The product meets ASTM F835 specifications for quality assurance and is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, ensuring safe use across global industrial markets.