S-91255A116 4-40 x 1" ASTM F835 Steel Button Head Hex-Drive Screws

Key Features & Benefits at a Glance

• Exceptional durability with 120,000 psi tensile strength and Rockwell C39 hardness for reliable performance in demanding industrial environments
• Superior corrosion resistance through black-oxide coating on alloy steel, extending service life in various operating conditions
• Precise thread engagement with Class 3A UNC coarse threads ensuring secure fastening and vibration resistance
• Easy installation and removal with 1/16" hex drive design providing excellent torque transmission and tool accessibility
• Versatile partial threading allowing for optimal clamp load distribution across the 1" length
• Space-saving rounded button head profile delivering a low-profile finish while maintaining high strength characteristics
• Comprehensive regulatory compliance meeting ASME B18.3, ASTM F835, RoHS 3, and REACH standards for global industrial applications

Professional Applications & Engineering Value

These 4-40 UNC rounded head screws deliver critical engineering solutions for industrial assembly challenges where space constraints and corrosion resistance are primary concerns. The black-oxide alloy steel construction provides superior protection against environmental factors while maintaining the high tensile strength required for structural applications. The coarse thread design ensures rapid installation and reliable performance in materials where fine threads might strip or fail. The partially threaded configuration allows for precise clamp load control, making these button head screws ideal for machinery, electronics enclosures, and precision equipment where vibration resistance and consistent fastening pressure are essential. The combination of hex drive functionality and rounded head profile addresses both installation efficiency and aesthetic requirements in professional settings.

Specification Summary & Compliance

These fasteners maintain Class 3A thread fit precision according to UNC standards, ensuring consistent engagement and reliability. Manufacturing complies with ASME B18.3 dimensional specifications and ASTM F835 performance requirements. Environmental compliance is verified through RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) certifications, confirming adherence to international substance restriction regulations for industrial components.