S-90550A830 5/16"-18 x 3/4" 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 thanks to 18-8 stainless steel construction, ideal for harsh industrial environments
• Enhanced durability and strength with Class 3A thread fit, ensuring reliable, vibration-resistant fastening
• Efficient pressure equalization via the vented design (0.078" vent diameter), preventing fluid or gas buildup
• Easy installation and removal with hex drive (3/16") and standard 82° countersink for flush mounting
• Wide compatibility with 5/16"-18 UNC coarse threading, suitable for various materials and applications
• Full regulatory compliance meeting ASME B18.3, ASTM F879, MIL-DTL-18240, RoHS 3, and REACH standards
• Consistent performance with fully threaded 3/4" length, providing secure holding power across the entire fastener

Professional Applications & Engineering Value

This 18-8 stainless steel flat head screw is engineered to address critical challenges in industrial settings, such as corrosion, pressure differentials, and vibration loosening. The vented design allows for pressure equalization, making it ideal for sealed systems in automotive, aerospace, and machinery where trapped gases or fluids could compromise integrity. Its Class 3A thread fit and UNC coarse threading ensure tight, reliable connections in materials like metal and composites, reducing the risk of thread stripping. The 82° countersink angle and flat head profile provide a smooth, flush finish, essential for applications requiring aerodynamic or aesthetic surfaces. Built to ASME B18.3 and MIL-DTL-18240 specifications, this screw delivers consistent performance in demanding environments, from manufacturing assemblies to military equipment, while its RoHS and REACH compliance supports sustainable, safe usage.

Specification Summary & Compliance

This screw features precise Class 3A thread fit with 5/16"-18 UNC coarse threading, ensuring high accuracy and interchangeability. It adheres to ASME B18.3, ASTM F879, and MIL-DTL-18240 manufacturing standards, guaranteeing dimensional consistency and reliability. Additionally, it is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, confirming it is free of hazardous substances and safe for industrial use.