S-91900A570 1/4"-28 x 1/2" ASME B18.3 Tamper-Resistant Torx Stainless Steel Button Head Screws

Key Features & Benefits at a Glance

• Enhanced tamper resistance with specialized T27 Torx drive that deters unauthorized removal in high-security environments
• Superior corrosion resistance through 18-8 stainless steel construction with passivated finish for extended service life in harsh conditions
• Exceptional mechanical strength with 70,000 psi tensile strength and Rockwell B70 hardness to withstand heavy loads and vibration
• Precise thread engagement with Class 3A UNF fine threads ensuring reliable fastening in critical applications
• Reduced surface damage from rounded button head design that minimizes marring on contact surfaces
• Full regulatory compliance meeting ASME B18.3 standards while being RoHS 3 and REACH compliant for global industrial use
• Complete thread coverage with fully threaded design providing consistent clamping force along the entire 1/2" length

Professional Applications & Engineering Value

These tamper-resistant Torx screws deliver critical security and reliability for industrial applications where unauthorized access poses significant risks. The 18-8 stainless steel composition combined with passivated finish provides exceptional resistance to corrosion, oxidation, and chemical exposure in demanding environments such as electrical enclosures, machinery guards, and public infrastructure. The Class 3A UNF fine threads ensure precise fitment and vibration resistance in assemblies requiring repeated maintenance. The specialized T27 drive system prevents casual tampering while allowing authorized personnel efficient installation and removal using proper tools. These rounded head screws are engineered to maintain integrity under sustained mechanical stress with their 70,000 psi tensile strength, making them ideal for security panels, access control systems, and industrial equipment requiring both protection and durability.

Specification Summary & Compliance

Manufactured to exacting ASME B18.3 specifications with Class 3A thread fit for superior dimensional accuracy. Features 1/4"-28 UNF fine threads in right-hand direction with full threading along the 1/2" length. Compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, ensuring safe use across various industrial sectors. The passivated finish on 18-8 stainless steel provides additional corrosion protection while maintaining the material's inherent strength characteristics.