S-91255A541 1/4"-20 x 7/8" ASTM F835 Steel Button Head Hex-Drive Screws

Key Features & Benefits at a Glance

• Exceptional Durability: Black-oxide alloy steel construction with Rockwell C39 hardness ensures long-lasting performance in demanding environments, resisting wear and corrosion.
• Superior Tensile Strength: With 120,000 psi tensile strength, this screw provides reliable fastening under high-stress conditions, reducing the risk of failure.
• Precise Thread Fit: Class 3A UNC coarse threads offer excellent engagement and vibration resistance, ensuring secure assemblies with minimal loosening.
• Easy Installation: Hex drive (5/32") and rounded button head design allow for straightforward tool access and a low-profile finish, speeding up assembly processes.
• Full Threading for Maximum Grip: Fully threaded shank distributes load evenly, enhancing holding power across the entire length for robust connections.
• Compliance with Industry Standards: Meets ASME B18.3 and ASTM F835 specifications, guaranteeing consistency and reliability for professional applications.
• Environmental and Safety Compliance: RoHS 3 and REACH compliant, making these screws safe for use in regulated industries without hazardous substances.

Professional Applications & Engineering Value

This Black-Oxide Alloy Steel Button Head Screw is engineered to address common industrial challenges, such as vibration-induced loosening and corrosion in harsh settings. The Class 3A UNC coarse threads provide a tight fit that resists back-out, ideal for machinery, automotive, and heavy equipment assemblies where reliability is critical. The black-oxide surface treatment enhances corrosion resistance, extending service life in humid or outdoor environments. Combined with a rounded head and hex drive, it ensures easy installation in confined spaces, reducing assembly time and improving efficiency. These features make it a top choice for engineers seeking high-strength fasteners that deliver consistent performance in demanding applications, from manufacturing to construction.

Specification Summary & Compliance

This screw features precise dimensions, including a 1/4"-20 UNC coarse thread with Class 3A fit for accurate engagement, and a length of 7/8" in the inch system. It complies with ASME B18.3 and ASTM F835 standards, ensuring manufacturing consistency. Additionally, it is RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) compliant, confirming adherence to environmental and safety regulations for industrial use.