S-91900A571 1/4"-28 x 3/4" ASME B18.3 Tamper-Resistant Torx Stainless Steel Button Head Screws
Tamper-Resistant Torx Stainless Steel Button Head Screws
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Basic Information
Head Parameters
Dimensions
Thread Parameters
Tip & Drive Parameters
Material & Strength
Temperature & Environment
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Key Features & Benefits at a Glance
- Enhanced tamper resistance with specialized Torx drive (T27 size) to prevent unauthorized access in high-security applications.
- Superior corrosion resistance from 18-8 stainless steel construction and passivated finish, ensuring longevity in harsh environments.
- High tensile strength of 70,000 psi provides reliable load-bearing capacity for demanding mechanical assemblies.
- Precise Class 3A thread fit with 1/4"-28 UNF fine threading for secure, vibration-resistant fastening in critical components.
- Rounded button head design offers a low-profile, smooth finish that reduces snagging and improves safety in exposed locations.
- Full compliance with ASME B18.3 and environmental regulations (RoHS 3, REACH) for assured quality and global supply chain suitability.
- Consistent performance backed by Rockwell B70 hardness and full threading for uniform engagement across the 3/4" length.
Professional Applications & Engineering Value
This tamper-resistant Torx screw is engineered to address critical security and durability challenges in industrial settings. The 18-8 stainless steel material, combined with a passivated finish, resists oxidation and chemical exposure, making it ideal for outdoor equipment, medical devices, and electronic enclosures. The Class 3A UNF fine thread ensures tight tolerances and minimal backlash, preventing loosening under vibration in machinery, transportation, or precision instruments. Its rounded head with T27 drive deters tampering while allowing efficient installation in confined spaces, providing a reliable fastening solution that meets rigorous ASME B18.3 standards for security-critical assemblies.
Specification Summary & Compliance
This screw adheres to Class 3A thread fit per UNF standards, with precise dimensions: 1/4"-28 thread size, 0.25" diameter, and 3/4" length. Manufacturing complies with ASME B18.3 specifications, ensuring consistent quality. It is fully RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) compliant, supporting environmentally responsible procurement. The fully threaded design and right-hand thread direction guarantee uniform performance across applications.
