S-91900A535 1/4"-20 x 1/4" ASME B18.3 Tamper-Resistant Torx Stainless Steel Button Head Screws

Key Features & Benefits at a Glance

• Superior tamper resistance with T27 Torx drive design to prevent unauthorized access in secure installations
• Exceptional corrosion resistance through 18-8 stainless steel construction and passivated finish for long-term reliability in harsh environments
• High mechanical strength with 70,000 psi tensile strength and Rockwell B70 hardness to withstand heavy loads and vibration
• Precise thread engagement with Class 3A thread fit ensuring secure fastening and reduced risk of stripping
• Full threading capability providing maximum grip length and uniform stress distribution across the entire fastener
• Regulatory compliance meeting ASME B18.3 standards and environmental regulations for global project acceptance
• Optimized head design with rounded button profile for reduced snagging and improved aesthetic integration

Professional Applications & Engineering Value

These 1/4"-20 UNC rounded head screws with tamper-resistant T27 drive address critical security and durability challenges in industrial settings. The 18-8 stainless steel material combined with passivated finish creates a robust barrier against corrosion, making them ideal for outdoor equipment, marine applications, and chemical processing facilities where environmental exposure is a concern. The Class 3A thread fit ensures precise mating with components, eliminating play and maintaining joint integrity under dynamic loads. Particularly valuable in public infrastructure, transportation systems, and secured enclosures, these security screws provide reliable protection against vandalism while maintaining the structural performance required for demanding mechanical assemblies.

Specification Summary & Compliance

Manufactured to exacting standards with UNC coarse threads in Class 3A fit for superior thread engagement and consistent performance. These fasteners comply with ASME B18.3 dimensional specifications and meet RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations. The combination of 70,000 psi tensile strength and Rockwell B70 hardness ensures reliable performance in high-stress applications while maintaining full compliance with industrial fastener standards.