S-91870A774 1/4"-20 x 3/8" ASME B18.3 Tamper-Resistant Torx Plus Steel Flat Head Screws

Key Features & Benefits at a Glance

• Enhanced tamper resistance with specialized Torx Plus IPR27 drive that prevents unauthorized access in secure environments
• Superior corrosion protection through black oxide finish, extending service life in demanding industrial conditions
• Exceptional mechanical strength with 160,000 psi tensile strength and Rockwell C38 hardness for heavy-duty applications
• Optimized flush mounting featuring undercut flat head design with 82° countersink angle for seamless surface integration
• Reliable thread engagement with Class 2A thread fit and coarse UNC threading ensuring secure fastening in vibration-prone applications
• Full-threaded design providing maximum grip length and uniform stress distribution across the entire fastener
• Regulatory compliance assurance meeting ASME B18.3 specifications while being RoHS 3 and REACH compliant for global industrial use

Professional Applications & Engineering Value

These alloy steel flat head screws with tamper-resistant Torx Plus drive address critical security and performance requirements in industrial settings. The combination of black oxide finish and high-strength alloy steel provides exceptional resistance to corrosion and mechanical stress, making them ideal for machinery, electronic enclosures, and public infrastructure where unauthorized access prevention is paramount. The undercut flat head profile with 82° countersink angle ensures flush mounting without protrusion, while the 1/4-20 UNC coarse threading delivers rapid installation and reliable performance in high-vibration environments. These fully threaded screws maintain consistent clamping force across the entire fastener length, preventing loosening in critical assemblies.

Specification Summary & Compliance

Manufactured to precise dimensional standards with Class 2A thread fit tolerance and UNC coarse thread specifications. Complies with ASME B18.3 manufacturing standards and maintains regulatory compliance with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) requirements. The screws feature right-hand threading, fully threaded design, and are engineered for consistent performance in industrial fastener applications.