S-93802A429 4-40 x 1/2" MIL-DTL-18240, MS3212-5L, NASM3212, NASM82496 Sealing Thread-Locking Stainless Steel Pan Head Phillips Screws

Key Features & Benefits at a Glance

• Superior sealing performance with silicone rubber O-ring, capable of withstanding pressures up to 6000 psi for leak-proof assemblies.
• Reliable vibration resistance through nylon patch thread locking, maintaining secure fastening in dynamic environments from -40° to 225° F.
• Exceptional corrosion resistance with 18-8 stainless steel and passivated finish, ensuring longevity in harsh industrial and aerospace conditions.
• Wide temperature compatibility with O-ring and thread locker materials functioning across -80° to 400° F, ideal for extreme operational ranges.
• High tensile strength of 70,000 psi provides robust mechanical performance for critical applications without failure.
• Easy installation and removal with Phillips No. 1 drive and pan head design, reducing assembly time and tool wear.
• Precision threading with Class 2A fit and UNC coarse thread ensures consistent engagement and reduces cross-threading risks.

Professional Applications & Engineering Value

This 4-40 UNC rounded head screw is engineered to address common challenges in aerospace, industrial machinery, and high-pressure fluid systems. The combination of 18-8 stainless steel material and passivated finish offers excellent resistance to oxidation and chemical exposure, while the silicone rubber O-ring and nylon patch thread locker work synergistically to prevent leaks and loosening under vibration. Its coarse UNC threading and Class 2A fit facilitate quick assembly with reliable torque retention, making it ideal for applications where maintenance access is limited and reliability is non-negotiable. By integrating sealing and locking features into a single MIL-DTL-18240 compliant component, it reduces part count and simplifies inventory for OEMs and MRO teams.

Specification Summary & Compliance

This screw features 4-40 UNC coarse threads with Class 2A thread fit for standard tolerance and interchangeability. It is fully threaded and manufactured to meet MIL-DTL-18240, NASM3212, and NASM82496 specifications, ensuring adherence to rigorous aerospace and defense standards. The product is RoHS 3 (2015/863/EU) Compliant and REACH (EC 1907/2006) Compliant, confirming its safety and environmental responsibility for global supply chains.