S-91870A757 5/16"-18 x 5/8" ASME B18.3 Tamper-Resistant Torx Stainless Steel Flat Head Screws

Key Features & Benefits at a Glance

• Enhanced tamper resistance with T40 Torx drive prevents unauthorized access in high-security environments
• Superior corrosion protection through 18-8 stainless steel construction and passivated finish for extended service life
• Maximum load-bearing capacity with 70,000 psi tensile strength and Rockwell B70 hardness for demanding applications
• Precision thread engagement with Class 3A UNC coarse threads ensuring reliable fastening in vibration-prone settings
• Optimal flush mounting with standard 82° countersink angle and flat head design for smooth surface finishes
• Full-thread coverage along the 5/8" length provides consistent clamping force across the entire fastener
• Regulatory compliance meeting ASME B18.3 standards and environmental regulations for global industrial use

Professional Applications & Engineering Value

This 18-8 stainless steel flat head screw addresses critical engineering challenges in industrial settings where security and corrosion resistance are paramount. The tamper-resistant T40 Torx drive prevents unauthorized disassembly in public infrastructure, machinery guards, and electronic enclosures, while the passivated finish enhances protection against chemicals, moisture, and environmental exposure. The Class 3A thread fit and UNC coarse threading ensure rapid installation and vibration resistance in assembly lines, transportation equipment, and outdoor structures. With its 82° countersink and fully threaded design, this fastener delivers reliable performance in metal fabrication, electrical panels, and heavy machinery where flush mounting and high tensile strength are essential for operational safety and longevity.

Specification Summary & Compliance

Manufactured to precise dimensional standards with Class 3A thread fit and UNC 5/16"-18 coarse threading for superior engagement. Complies with ASME B18.3 specifications for flat head screw geometry and mechanical properties. Meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, ensuring safe use in industrial applications worldwide. The 82° countersink angle conforms to standard flat head profiles for seamless integration with compatible components.