S-90517A130 4-40 x 1/2" ASME B18.3 Tamper-Resistant Hex Drive Flat Head Screws
Tamper-Resistant Hex Drive Flat 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 hex drive design prevents unauthorized removal in high-security environments
- Superior corrosion protection through 18-8 stainless steel construction and passivated surface treatment
- Reliable high-strength performance with 70,000 psi tensile strength and Rockwell B55 hardness rating
- Precision thread engagement featuring Class 3A fit and UNC coarse threads for secure fastening
- Full-threaded design ensures maximum grip length and uniform stress distribution
- Industry-standard compliance meeting ASME B18.3 specifications for consistent quality
- Environmental regulation adherence with RoHS 3 and REACH compliance for global applications
Professional Applications & Engineering Value
These 4-40 UNC flat head screws with tamper-resistant hex drive address critical security and durability challenges in industrial settings. The combination of 18-8 stainless steel material and passivated finish provides exceptional resistance to corrosion, making them ideal for harsh environments where moisture or chemicals are present. The Class 3A thread fit ensures precise engagement with mating components, reducing the risk of stripping or cross-threading during installation. The flat head design with 82° countersink angle creates a flush surface finish, essential for applications where protruding fasteners could interfere with mechanical operation or pose safety hazards. These security screws are particularly valuable in public infrastructure, electrical enclosures, and machinery where unauthorized access prevention is paramount.
Specification Summary & Compliance
Manufactured to exacting standards with Class 3A thread fit and UNC coarse thread spacing for optimal performance. These fully threaded screws maintain dimensional accuracy per ASME B18.3 specifications and demonstrate compliance with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations. The right-hand thread direction and standardized dimensions ensure compatibility with industry-standard installation tools and procedures.
