S-91870A440 M4 x 6 mm ASTM F879M Tamper-Resistant Torx Stainless Steel Flat Head Screws

Key Features & Benefits at a Glance

• Enhanced Security: Tamper-resistant T20 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.
• Reliable Fastening Strength: High 80,000 psi tensile strength and Rockwell B96 hardness ensure long-term joint integrity under stress.
• Precision Thread Fit: Class 6g coarse threads provide quick, secure engagement and reduce cross-threading risks.
• Flush Mounting Design: Flat head with 90° countersink allows for a smooth, unobtrusive surface finish.
• Full Thread Engagement: Fully threaded M4 x 0.7mm design maximizes grip and load distribution along the entire length.
• Global Compliance: Meets ASTM F879M specifications and is RoHS 3 & REACH compliant for safe, regulated use.

Professional Applications & Engineering Value

This M4 tamper-resistant Torx flat head screw is engineered to address critical needs in security-sensitive and demanding industrial environments. The 18-8 stainless steel construction, enhanced by a passivated finish, provides exceptional resistance to corrosion and oxidation, making it suitable for outdoor equipment, electronic enclosures, and machinery exposed to moisture or chemicals. The tamper-resistant T20 drive is a key feature for applications where vandalism or unauthorized access is a concern, such as in public infrastructure, telecommunications, and security panels. Its fully threaded metric coarse thread (M4 x 0.7mm) ensures rapid installation and high clamp force, while the flat head design sits flush to prevent snagging and maintain aesthetic appeal. This combination of security, durability, and precision delivers reliable performance for OEMs and maintenance teams requiring trusted industrial fasteners.

Specification Summary & Compliance

This screw features a Metric M4 x 0.7mm thread with a Class 6g tolerance for precise fit, right-hand direction, and coarse spacing. It is manufactured in compliance with ASTM F879M standards and is verified to be RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) compliant, ensuring adherence to environmental and safety regulations for industrial and commercial use.