S-91900A106 4-40 x 1/4" ASME B18.3 Tamper-Resistant Torx Stainless Steel Button Head Screws

Key Features & Benefits at a Glance

• Enhanced tamper-resistance with specialized Torx T8 drive to prevent unauthorized access in secure installations
• Superior corrosion protection through 18-8 stainless steel construction and passivated finish for long-term reliability in harsh environments
• Precise thread engagement with Class 3A fit and 4-40 UNC coarse threading ensuring secure fastening and vibration resistance
• High mechanical strength offering 70,000 psi tensile strength and Rockwell B70 hardness for demanding industrial applications
• Streamlined installation with rounded button head profile providing low-clearance fit and reduced snagging
• Full regulatory compliance meeting ASME B18.3 standards plus RoHS 3 and REACH environmental regulations
• Complete thread coverage with fully threaded 1/4" length for maximum grip strength across the entire fastener

Professional Applications & Engineering Value

These 18-8 stainless steel rounded head screws deliver critical security and reliability for industrial applications where tampering prevention and environmental durability are paramount. The tamper-resistant Torx T8 drive system provides superior anti-vandalism protection compared to standard fasteners, making them ideal for security panels, access control systems, and public infrastructure. The combination of passivated finish and stainless steel material ensures exceptional corrosion resistance in moisture-prone environments, while the 4-40 UNC coarse threading with Class 3A precision prevents loosening under vibration. The rounded button head profile offers a clean, low-profile appearance while minimizing clearance requirements, solving space-constrained installation challenges in electronic enclosures and machinery guards.

Specification Summary & Compliance

Manufactured to exacting ASME B18.3 standards with precision Class 3A thread fit for superior engagement. Features 4-40 UNC coarse threads with right-hand direction and full threading along the 1/4" length. Compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, ensuring safe use across various industries. Mechanical properties include 70,000 psi tensile strength and Rockwell B70 hardness for reliable performance in demanding applications.