S-95635A263 4-40 x 1/2" ASME B18.3 Tamper-Resistant Hex-Drive Stainless Steel Button Head Screws

Key Features & Benefits at a Glance

• Enhanced tamper resistance with specialized hex drive that prevents unauthorized removal in high-security applications
• Superior corrosion protection through 18-8 stainless steel construction and passivated finish for extended service life in harsh environments
• Exceptional mechanical strength with 70,000 psi tensile strength and Rockwell B70 hardness for reliable performance under stress
• Precision thread engagement with Class 3A fit and UNC coarse threads ensuring secure fastening and vibration resistance
• Streamlined installation with rounded button head profile that reduces snagging and provides a finished appearance
• Full regulatory compliance meeting ASME B18.3 standards and environmental regulations including RoHS 3 and REACH
• Complete thread coverage with fully threaded design for maximum grip strength across the entire fastener length

Professional Applications & Engineering Value

This 4-40 UNC thread screw with tamper-resistant hex drive addresses critical security and durability challenges in industrial settings. The 18-8 stainless steel construction combined with passivated finish provides exceptional resistance to corrosion, oxidation, and chemical exposure, making it ideal for electronics enclosures, medical devices, and outdoor equipment where environmental factors would compromise ordinary fasteners. The Class 3A thread fit ensures precise engagement with mating components, reducing the risk of cross-threading while maintaining consistent clamping force. The rounded button head design minimizes protrusion risks in applications where clearance is limited, while the specialized drive system deters tampering in public access equipment, transportation systems, and secured facilities without sacrificing installation efficiency.

Specification Summary & Compliance

This fastener features precision 4-40 UNC coarse threads with Class 3A fit for superior thread engagement and meets ASME B18.3 dimensional specifications. The screw maintains 1/2" length with fully threaded design and right-hand thread direction. Compliance includes RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, ensuring suitability for global markets and restricted substance requirements.