S-91900A105 4-40 x 3/16" ASME B18.3 Tamper-Resistant Torx Stainless Steel Button Head Screws

Key Features & Benefits at a Glance

• Enhanced tamper resistance with a specialized T8 Torx drive that deters unauthorized access, ideal for securing sensitive equipment and public infrastructure.
• Superior corrosion resistance thanks to 18-8 stainless steel construction and a passivated finish, ensuring long-term reliability in harsh or outdoor environments.
• High tensile strength of 70,000 psi and Rockwell B70 hardness for dependable performance under mechanical stress, reducing the risk of fastener failure.
• Precise Class 3A thread fit and coarse UNC threading for faster installation, improved grip, and consistent engagement in various materials.
• Full threading along the 3/16" length provides maximum holding power and flexibility in assembly, accommodating different material thicknesses.
• Compliance with ASME B18.3, RoHS 3, and REACH standards guarantees product quality, safety, and environmental responsibility for global industrial use.
• Rounded button head design offers a low-profile, smooth finish that minimizes snagging and enhances aesthetic appeal in finished products.

Professional Applications & Engineering Value

Engineered for high-security and demanding environments, these 4-40 UNC tamper-resistant Torx screws address critical challenges in industrial and commercial settings. The 18-8 stainless steel material, combined with a passivated finish, provides exceptional resistance to rust and chemical exposure, making them suitable for outdoor fixtures, electronic enclosures, and medical devices. The T8 tamper-resistant drive prevents vandalism and unauthorized disassembly, ensuring operational integrity in public access areas, transportation systems, and secured machinery. With a Class 3A thread fit and coarse UNC threading, these screws enable quick, reliable fastening in metals and plastics, reducing assembly time while maintaining high tensile strength for vibration-prone applications.

Specification Summary & Compliance

This screw features a 4-40 UNC thread size with Class 3A fit for precise tolerance and optimal performance. It is fully threaded, measures 3/16" in length, and complies with ASME B18.3 specifications for dimensional accuracy. The product is also RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) compliant, adhering to environmental and safety regulations for industrial use.