S-90550A810 5/16"-18 x 1/2" ASME B18.3, ASTM F879, MIL-DTL-18240 Venting Stainless Steel Hex-Drive Flat Head Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with 18-8 stainless steel construction for long-lasting performance in harsh environments
• Enhanced torque transmission through the hex drive design, ensuring secure fastening and reduced tool slippage
• Reliable thread engagement with Class 3A thread fit and coarse UNC threading for quick assembly and vibration resistance
• Optimal flush mounting with standard flat head profile and 82° countersink angle for smooth surface finishes
• Pressure equalization capability via vented screw design to prevent pressure buildup in sealed applications
• Full regulatory compliance meeting ASME B18.3, ASTM F879, and MIL-DTL-18240 standards for guaranteed quality and interoperability
• Environmental safety assurance with RoHS 3 and REACH compliance for sustainable industrial use

Professional Applications & Engineering Value

This 18-8 stainless steel flat head screw delivers exceptional engineering value in demanding industrial environments where corrosion resistance and mechanical reliability are paramount. The 5/16"-18 UNC coarse threading combined with Class 3A thread fit ensures rapid installation and maintains secure fastening under vibration, making it ideal for machinery, equipment assembly, and structural applications. The hex drive design provides superior torque transmission compared to slotted drives, reducing installation time and preventing damage to fastener heads. The vented feature addresses critical pressure equalization needs in sealed systems, while the 82° countersink angle creates clean, flush surfaces in precision applications. Manufactured to ASME B18.3, ASTM F879, and MIL-DTL-18240 specifications, this screw offers guaranteed performance consistency across aerospace, automotive, and industrial manufacturing sectors.

Specification Summary & Compliance

This flat head hex drive screw features precision 5/16"-18 UNC coarse threading with Class 3A thread fit for superior dimensional accuracy and engagement. The fully threaded design and standard flat head profile with 82° countersink angle ensure consistent performance across applications. Manufacturing compliance includes ASME B18.3, ASTM F879, and MIL-DTL-18240 specifications, guaranteeing interchangeability and reliability. Environmental compliance is verified through RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring safe usage in regulated industries.