S-91870A450 M4 x 8 mm ASTM F879M Tamper-Resistant Torx Stainless Steel Flat Head Screws

Key Features & Benefits at a Glance

• Enhanced tamper resistance with specialized T20 Torx drive that deters unauthorized access in secure environments
• Superior corrosion resistance from 18-8 stainless steel construction with passivated finish for extended service life in harsh conditions
• High mechanical strength with 80,000 psi tensile strength and Rockwell B96 hardness for reliable performance under load
• Precision thread engagement with Class 6g metric coarse threads ensuring consistent fastening and vibration resistance
• Optimal flush mounting with standard 90° flat head profile that sits perfectly countersunk in prepared surfaces
• Full regulatory compliance meeting ASTM F879M, RoHS 3, and REACH standards for global industrial applications
• Complete thread coverage with fully threaded 8mm length providing maximum grip strength across the entire fastener

Professional Applications & Engineering Value

This M4 tamper-resistant flat head screw delivers critical security and reliability for industrial applications where unauthorized access poses significant risks. The 18-8 stainless steel material with passivated finish provides exceptional resistance to corrosion, chemicals, and environmental factors, making it ideal for outdoor equipment, marine applications, and harsh manufacturing environments. The specialized T20 Torx drive requires matching security tools, preventing tampering in public infrastructure, electrical enclosures, and machinery safety guards. With its Class 6g thread fit and 0.7mm coarse pitch, installation is streamlined while maintaining vibration resistance in high-stress applications. The fully threaded design ensures maximum holding power across the entire 8mm length, providing engineers with a reliable fastening solution that meets rigorous ASTM F879M standards for consistent performance.

Specification Summary & Compliance

This metric fastener features precision M4 x 0.7mm coarse threads with Class 6g tolerance for optimal fit and performance. Manufacturing complies with ASTM F879M specifications for dimensional accuracy and mechanical properties. The screw maintains full compliance with RoHS 3 (2015/863/EU) restrictions on hazardous substances and REACH (EC 1907/2006) regulations for chemical safety. The right-hand thread direction and standard 90° countersink angle ensure compatibility with standard metric flat head applications across industrial sectors.