S-91870A240 1/4"-20 x 1/2" ASME B18.3 Tamper-Resistant Torx Stainless Steel Flat Head Screws

Key Features & Benefits at a Glance

• Enhanced tamper resistance with T27 Torx drive prevents unauthorized access in high-security applications
• Superior corrosion protection through 18-8 stainless steel construction and passivated surface treatment
• Exceptional mechanical strength with 70,000 psi tensile strength and Rockwell B70 hardness for demanding environments
• Optimized flush mounting featuring undercut flat head design with 82° countersink angle for seamless installation
• Reliable thread engagement with full UNC coarse threading and Class 2A fit ensuring consistent fastening performance
• Broad industrial compliance meeting ASME B18.3 standards and environmental regulations including RoHS 3 and REACH
• Right-hand thread configuration provides standard installation familiarity while maintaining security features

Professional Applications & Engineering Value

This 18-8 stainless steel flat head screw delivers critical security and durability for industrial applications where tampering prevention and environmental resistance are paramount. The combination of tamper-resistant T27 Torx drive and passivated finish creates a robust fastening solution that withstands corrosive environments while deterring unauthorized access. Engineers specify these security screws for machinery enclosures, electrical panels, public infrastructure, and transportation equipment where vibration resistance and long-term reliability are essential. The undercut flat head profile with 82° countersink ensures flush mounting in precision applications, while the fully threaded UNC coarse pattern provides maximum grip strength in various materials. These industrial screws maintain integrity in demanding conditions, making them ideal for OEM manufacturing, maintenance operations, and security-sensitive installations.

Specification Summary & Compliance

This fastener maintains precise Class 2A thread fit tolerance with 1/4"-20 UNC coarse threading and right-hand direction. Manufacturing complies with ASME B18.3 specifications for dimensional accuracy and performance. Environmental compliance includes RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring safe use in restricted substance-sensitive applications. The screw features complete threading along the 1/2" length with consistent 0.25" thread diameter for reliable engagement across industrial fastening requirements.