S-90517A513 1/4"-20 x 3/4" ASME B18.3 Tamper-Resistant Hex Drive Flat Head Screws

Key Features & Benefits at a Glance

• Tamper-resistant security with specialized hex drive design to prevent unauthorized access in sensitive applications
• Superior corrosion resistance through 18-8 stainless steel construction and passivated surface treatment
• Exceptional mechanical strength delivering 70,000 psi tensile strength and Rockwell B55 hardness for heavy-duty applications
• Precision threading performance with Class 3A UNC coarse threads ensuring reliable engagement and vibration resistance
• Optimized flush mounting featuring standard 82° countersink angle for seamless surface integration
• Regulatory compliance assurance meeting ASME B18.3 standards and environmental regulations for global industrial use
• Enhanced durability through fully threaded design providing maximum holding power across the entire fastener length

Professional Applications & Engineering Value

This 18-8 stainless steel tamper-resistant flat head screw addresses critical engineering challenges in industrial settings where both security and environmental resistance are paramount. The passivated finish significantly enhances corrosion protection, making it ideal for harsh environments including outdoor installations, chemical processing equipment, and marine applications. The tamper-resistant hex drive provides essential security for public infrastructure, electrical enclosures, and machinery where unauthorized access prevention is crucial. With its Class 3A UNC coarse threading and 82° countersink angle, this fastener ensures precise installation and reliable performance in high-vibration environments while maintaining a flush surface profile for safety and aesthetics. The combination of 70,000 psi tensile strength and Rockwell B55 hardness delivers exceptional load-bearing capacity for demanding mechanical assemblies and structural applications.

Specification Summary & Compliance

This 1/4"-20 x 3/4" flat head screw features precision Class 3A thread fit with UNC coarse threading for optimal engagement and vibration resistance. Manufactured in compliance with ASME B18.3 specifications for dimensional accuracy and performance standards. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, ensuring safe use across global industrial markets. The 5/32" tamper-resistant hex drive and standard flat head profile maintain consistent installation characteristics while the fully threaded design provides maximum fastening capability throughout the entire screw length.