S-92805A280 4-40 x 5/16" MIL-DTL-18240 Stainless Steel Thread-Locking Hex Drive Flat Head Screws

Key Features & Benefits at a Glance

• Exceptional corrosion resistance with 18-8 stainless steel construction, ideal for harsh environments and long-term reliability
• Superior vibration resistance provided by the nylon patch thread locker, maintaining secure fastening from -70° to 250°F
• High-strength performance with 70,000 psi tensile strength and Rockwell B55 hardness for demanding industrial applications
• Precise, reliable threading with Class 3A thread fit and UNC coarse thread profile ensuring consistent engagement and reduced cross-threading risk
• Easy installation and removal using the standard hex drive, compatible with common tools for efficient assembly
• Flush mounting capability with the flat head and 82° countersink angle for a smooth, unobtrusive finish in precision assemblies
• Regulatory compliance assurance meeting MIL-DTL-18240, RoHS, and REACH standards for quality and environmental safety

Professional Applications & Engineering Value

This 4-40 UNC flat head screw is engineered to address critical challenges in precision assembly and vibration-prone environments. The 18-8 stainless steel material offers excellent resistance to corrosion and oxidation, making it suitable for electronics, aerospace, and marine applications where durability is paramount. The nylon patch thread locker effectively prevents loosening under dynamic loads, eliminating the need for additional locking hardware and reducing maintenance. With a fully threaded design and Class 3A thread fit, it ensures tight tolerances and reliable performance in coarse thread applications, providing secure fastening in machinery, enclosures, and structural components. Its hex drive and flat head profile facilitate quick installation in countersunk holes, streamlining production workflows while maintaining a clean aesthetic.

Specification Summary & Compliance

This screw features a 4-40 UNC thread size with Class 3A thread fit for high precision, and is fully threaded for consistent holding power. It complies with MIL-DTL-18240 specifications, ensuring adherence to rigorous military standards for reliability. Additionally, it is RoHS 3 (2015/863/EU) Compliant and REACH (EC 1907/2006) Compliant, meeting environmental and safety regulations for global industrial use.