S-91870A370 M3.5 x 20 mm ASTM F879M Tamper-Resistant Torx Stainless Steel Flat Head Screws

Key Features & Benefits at a Glance

• Enhanced Security: Tamper-resistant T15 Torx drive prevents unauthorized removal, ideal for public or high-security installations.
• Superior Corrosion Resistance: Made from 18-8 Stainless Steel with a passivated finish for excellent durability in harsh environments.
• High Mechanical Strength: Withstands up to 80,000 psi tensile strength and Rockwell B96 hardness for reliable, long-term performance.
• Precision Thread Fit: Class 6g thread fit ensures easy assembly and a secure, vibration-resistant connection.
• Optimized for Flush Mounting: Standard flat head with a 90° countersink angle provides a smooth, unobtrusive surface finish.
• Broad Industrial Compliance: Meets ASTM F879M specifications and is RoHS 3 & REACH compliant for safe, regulated use.
• Full Thread Engagement: Fully threaded M3.5 x 0.6mm coarse thread design offers maximum grip and holding power.

Professional Applications & Engineering Value

This M3.5 flat head screw is engineered to address critical challenges in industrial assembly and security-sensitive applications. The 18-8 stainless steel construction, enhanced by a passivated finish, provides exceptional corrosion resistance, making it suitable for outdoor equipment, marine hardware, and chemical processing environments where moisture and corrosive agents are present. The tamper-resistant Torx (T15) drive is a key feature for preventing vandalism and unauthorized access in public infrastructure, electronic enclosures, and transportation systems. Its fully threaded design with a coarse thread pitch ensures rapid installation and high pull-out strength, while the flat head profile allows for a clean, flush finish that minimizes protrusion and snagging risks. This combination of material durability and security design delivers long-term reliability and reduced maintenance needs for engineers and OEMs.

Specification Summary & Compliance

This metric screw features precise M3.5 x 0.6mm coarse threads with a Class 6g thread fit for consistent, reliable fastening. It is manufactured in compliance with ASTM F879M standards, ensuring mechanical and dimensional consistency. The product is also verified to be RoHS 3 (2015/863/EU) Compliant and REACH (EC 1907/2006) Compliant, confirming it is free of hazardous substances and safe for use in regulated markets.