S-90484A163 4-40 x 1/2" ASME B18.3, ASTM F835 Tamper-Resistant Hex-Drive Steel Button Head Screws

Key Features & Benefits at a Glance

• Superior tamper resistance with specialized hex drive design prevents unauthorized access in security-sensitive applications
• Exceptional mechanical strength with 130,000 PSI tensile strength and Rockwell C39 hardness withstands high-stress industrial environments
• Enhanced corrosion protection through black-oxide coating extends service life in demanding conditions
• Precision thread engagement with Class 3A fit ensures reliable fastening and vibration resistance
• Optimized installation efficiency with coarse UNC threads and fully threaded design speeds assembly processes
• Regulatory compliance assurance meets ASME B18.3, ASTM F835, RoHS 3, and REACH standards for global industrial applications
• Secure rounded head profile combines tamper-resistant functionality with smooth, low-profile appearance

Professional Applications & Engineering Value

Engineered for critical applications where security and reliability are paramount, these 4-40 UNC thread screws deliver exceptional performance in industrial machinery, electronic enclosures, and public infrastructure. The black-oxide alloy steel construction provides superior corrosion resistance while maintaining the 130,000 PSI tensile strength required for high-stress environments. The tamper-resistant hex drive design prevents unauthorized disassembly, making these rounded head screws ideal for security panels, access control systems, and maintenance-free installations. The coarse thread spacing ensures quick installation and reliable holding power in various materials, while the Class 3A thread fit guarantees precise engagement and vibration resistance throughout the product lifecycle.

Specification Summary & Compliance

These rounded head screws feature precise 4-40 UNC coarse threads with Class 3A fit tolerance for optimal engagement and reliability. Manufacturing complies with ASME B18.3 specifications and ASTM F835 standards for consistent quality and performance. The products are fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, ensuring safe use in global markets. The black-oxide surface treatment on alloy steel provides enhanced corrosion protection while maintaining the mechanical properties required for industrial applications.