S-92805A106 4-40 x 1/4" ASME B18.3, ASTM F879, MIL-DTL-18240 Stainless Steel Thread-Locking Hex Drive Flat Head Screws

Key Features & Benefits at a Glance

• Vibration-resistant locking with nylon patch thread locker maintains secure fastening in temperatures from -65° to 250°F, reducing maintenance needs in dynamic environments.
• Superior corrosion resistance from 18-8 stainless steel construction ensures long-term reliability in harsh industrial or outdoor applications.
• High tensile strength of 70,000 psi provides dependable load-bearing capacity for critical assemblies, minimizing failure risks.
• Precision Class 3A thread fit guarantees consistent engagement and ease of installation, reducing cross-threading and assembly time.
• Hex drive design (1/16") allows for high-torque application with standard tools, enhancing installation efficiency and grip.
• Full threading and 82° countersink enable flush mounting and uniform stress distribution, ideal for aerodynamic or aesthetic surfaces.
• Compliance with major standards including ASME B18.3, ASTM F879, and MIL-DTL-18240 ensures interoperability and quality assurance in regulated industries.

Professional Applications & Engineering Value

These 4-40 UNC flat head screws are engineered to address common challenges in precision assemblies, such as vibration-induced loosening and corrosion in demanding environments. The 18-8 stainless steel material offers excellent resistance to oxidation and chemicals, making them suitable for aerospace, electronics, and automotive applications where durability is critical. The nylon patch thread locker provides reliable locking without requiring additional adhesives, simplifying inventory and assembly processes. With a coarse thread spacing and right-hand thread direction, these screws facilitate quick installation in metals and plastics, while the flat head profile and 82° countersink angle ensure a seamless finish that meets aesthetic and functional requirements. Ideal for securing components in machinery, enclosures, and structural frames, they deliver consistent performance under stress, backed by high tensile strength and hardness ratings.

Specification Summary & Compliance

These screws feature a Class 3A thread fit per UNC standards, ensuring tight tolerances for reliable threading. They are manufactured in compliance with ASME B18.3, ASTM F879, and MIL-DTL-18240 specifications, guaranteeing consistency and safety. Environmental regulations are met with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) compliance, supporting sustainable procurement practices.