S-90484A160 4-40 x 3/16" 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 requiring unique tools, preventing unauthorized access in sensitive installations
• Exceptional durability from Rockwell C39 hardness alloy steel, maintaining structural integrity under repeated stress
• High-load capacity with 130,000 psi tensile strength, reliably securing critical components in demanding applications
• Precision thread engagement through Class 3A fit and UNC coarse threading, ensuring consistent fastening performance
• Corrosion-resistant protection from black-oxide surface treatment, extending service life in challenging environments
• Full-thread design providing maximum grip along the entire 3/16" length, eliminating potential weak points
• Regulatory compliance assurance meeting ASME B18.3, RoHS 3, and REACH standards for global industrial acceptance

Professional Applications & Engineering Value

These 4-40 UNC thread rounded head screws deliver critical security and reliability for industrial applications where tampering prevention and consistent performance are paramount. The black-oxide alloy steel construction provides excellent corrosion resistance while maintaining the 130,000 psi tensile strength necessary for high-stress environments. The tamper-resistant hex drive design ensures that secured components remain protected in public access equipment, electronic enclosures, and machinery requiring controlled maintenance access. With Class 3A thread fit precision and fully threaded engagement, these fasteners eliminate vibration-induced loosening in automotive assemblies, industrial controls, and precision instrumentation. The rounded button head profile offers a low-profile installation that reduces snagging hazards while providing ample bearing surface for secure fastening.

Specification Summary & Compliance

Manufactured to exacting ASME B18.3 specifications with Class 3A thread fit tolerance for superior engagement. The UNC coarse threading (4-40 size) ensures reliable performance in various materials. Compliant with RoHS 3 (2015/863/EU) environmental directives and REACH (EC 1907/2006) regulations for hazardous substances. Features include 3/16" length, 3/32" tamper-resistant hex drive, and black-oxide surface treatment on alloy steel substrate with Rockwell C39 hardness rating.