S-91255A549 1/4"-20 x 3" ASTM F835 Steel Button Head Hex-Drive Screws

Key Features & Benefits at a Glance

• Exceptional Durability: Crafted from black-oxide alloy steel with a Rockwell C39 hardness, providing superior resistance to wear and deformation in demanding environments.
• High Tensile Strength: Rated at 120,000 psi, ensuring reliable performance under heavy loads and reducing the risk of fastener failure.
• Precision Thread Fit: UNC coarse threading with Class 3A fit offers excellent engagement and vibration resistance, minimizing loosening in dynamic applications.
• Corrosion-Resistant Finish: Black-oxide coating enhances corrosion protection, extending service life in industrial settings.
• Easy Installation: Hex drive (5/32") and rounded button head design allow for straightforward tool access and a low-profile, snag-resistant finish.
• Regulatory Compliance: Meets ASME B18.3 and ASTM F835 standards, and is RoHS 3 and REACH compliant for safe, global use.
• Versatile Fastening: Partially threaded design with 1" minimum thread length provides flexibility for various assembly needs without unnecessary bulk.

Professional Applications & Engineering Value

This 1/4"-20 x 3" black-oxide alloy steel rounded head hex screw is engineered to address common industrial challenges such as vibration-induced loosening and material fatigue. The UNC coarse thread and Class 3A fit ensure tight, secure fastening in machinery, automotive assemblies, and heavy equipment, where precision and reliability are critical. The black-oxide finish not only resists corrosion but also reduces galling during installation, saving time and maintenance costs. With a high tensile strength of 120,000 psi and Rockwell C39 hardness, it withstands extreme forces, making it ideal for structural applications, construction projects, and manufacturing lines that demand long-term durability and compliance with ASME B18.3 and ASTM F835 standards.

Specification Summary & Compliance

This screw features precise UNC coarse threading with a Class 3A thread fit for accurate engagement and dimensional consistency. It adheres to ASME B18.3 and ASTM F835 manufacturing specifications, ensuring quality and interoperability. Additionally, it is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, confirming its suitability for environmentally conscious and global industrial use without hazardous substances.