S-90273A585 5/16"-18 x 1 1/4" ASME B18.6.3 Steel Phillips Flat Head Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with zinc-plated steel construction, extending service life in demanding industrial environments
• Exceptional load-bearing capacity with 60,000 psi tensile strength and Rockwell B70 hardness for reliable performance under stress
• Precise thread engagement with Class 2A fit and UNC coarse threads ensuring secure fastening and vibration resistance
• Optimal flush mounting with standard 82° countersink angle and flat head design for smooth surface finishes
• Efficient installation with No. 4 Phillips drive providing positive torque transfer and reduced cam-out risk
• Full-threaded design maximizing grip length and pull-out resistance across the entire 1-1/4" length
• Regulatory compliance meeting ASME B18.6.3 specifications and environmental standards for global industrial applications

Professional Applications & Engineering Value

These zinc-plated steel flat head screws deliver critical engineering solutions where surface flushness and structural integrity are paramount. The 5/16"-18 UNC coarse threading provides excellent engagement in various materials while resisting vibration-induced loosening - a common failure point in machinery and equipment assembly. The 82° countersink angle ensures proper seating in standard chamfered holes, creating smooth finished surfaces essential for automotive panels, electrical enclosures, and manufacturing fixtures. With 60,000 psi tensile strength and Rockwell B70 hardness, these Phillips drive screws maintain clamping force in high-stress applications without thread deformation. The zinc plating offers sacrificial corrosion protection, making them suitable for industrial environments where moisture or chemicals are present while maintaining compliance with international standards.

Specification Summary & Compliance

Manufactured to exacting ASME B18.6.3 specifications with Class 2A thread fit tolerances ensuring consistent performance. Features UNC coarse threads with right-hand direction and standard flat head profile. Full regulatory compliance with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental standards, confirming suitability for global industrial supply chains. The combination of precise dimensional control and material properties delivers reliable fastening performance across automotive, machinery, and general industrial applications.