S-91255A107 4-40 x 5/16" ASTM F835 Steel Button Head Hex-Drive Screws

Key Features & Benefits at a Glance

• Exceptional tensile strength of 120,000 psi for reliable performance in demanding applications
• Superior corrosion resistance from black-oxide coating on alloy steel, extending service life
• Precise Class 3A thread fit ensures secure fastening and vibration resistance
• Hex drive design (1/16") allows for easy installation with standard tools and reduced slipping
• Fully threaded UNC coarse thread provides maximum grip and faster assembly in various materials
• Rounded button head profile offers a low-profile, flush finish for enhanced safety and aesthetics
• Compliance with major standards including ASME B18.3 and ASTM F835 for guaranteed quality and interoperability

Professional Applications & Engineering Value

These 4-40 UNC coarse thread screws are engineered to address common industrial challenges such as material fatigue and assembly efficiency. The black-oxide alloy steel construction provides excellent durability against wear and environmental exposure, making them ideal for machinery, electronics, and automotive components where consistent performance is critical. The fully threaded design and Class 3A fit ensure tight, reliable connections that resist loosening under vibration, while the hex drive simplifies installation in confined spaces. By meeting rigorous standards like ASME B18.3, these screws deliver dependable engineering value in high-stress environments, reducing maintenance needs and downtime.

Specification Summary & Compliance

This product features precise UNC coarse threads with a Class 3A fit for tight tolerances, and dimensions including a 5/16" length and 1/16" hex drive. It complies with ASME B18.3 and ASTM F835 manufacturing specifications, and meets environmental standards such as RoHS 3 (2015/863/EU) and REACH (EC 1907/2006), ensuring safety and regulatory adherence for industrial use.