S-91255A115 4-40 x 7/8" ASTM F835 Steel Button Head Hex-Drive Screws

Key Features & Benefits at a Glance

• Exceptional durability with Black-Oxide Alloy Steel construction providing superior corrosion resistance in harsh industrial environments
• Maximum fastening reliability achieved through 120,000 psi tensile strength and Rockwell C39 hardness for heavy-duty applications
• Precise thread engagement with Class 3A thread fit ensuring tight, secure connections in critical assemblies
• Easy installation and removal with hex drive design allowing for efficient torque application and maintenance access
• Versatile coarse threading (UNC) providing excellent grip and rapid installation across various materials
• Full threading capability enabling consistent fastening strength along the entire 7/8" length
• Comprehensive compliance with ASME B18.3, ASTM F835, RoHS 3, and REACH standards for guaranteed quality and safety

Professional Applications & Engineering Value

These 4-40 UNC rounded head hex drive screws deliver exceptional engineering value in demanding industrial applications where reliability is paramount. The Black-Oxide Alloy Steel construction provides superior corrosion resistance, making them ideal for machinery, electronic enclosures, and automotive assemblies exposed to challenging environments. The Class 3A thread fit ensures precise mating with nuts and tapped holes, eliminating play and vibration-induced loosening in precision equipment. The button head design offers a low-profile finish while the hex drive facilitates high-torque installation without cam-out issues. With fully threaded construction and coarse thread spacing, these screws provide maximum holding power in metal, plastic, and composite materials, making them essential for maintenance, repair, and original equipment manufacturing operations.

Specification Summary & Compliance

This 4-40 UNC screw features precise Class 3A thread fit tolerances with coarse thread spacing, ensuring optimal engagement and reliability. Manufactured to exacting standards including ASME B18.3 and ASTM F835 specifications, these screws maintain consistent dimensional accuracy and performance characteristics. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, confirming they contain no restricted substances and meet the latest international safety standards for industrial applications.