S-93802A421 4-40 x 1/4" MIL-DTL-18240, MS3212-1L, NASM3212, NASM82496 Sealing Thread-Locking Stainless Steel Pan Head Phillips Screws

Key Features & Benefits at a Glance

• Superior sealing performance with a silicone rubber O-ring that withstands temperatures from -80° to 400° F and pressures up to 6000 psi, preventing leaks in demanding environments.
• Reliable vibration resistance thanks to the nylon patch thread locker, which maintains a secure hold in temperatures from -40° to 225° F, reducing maintenance needs.
• High tensile strength of 70,000 psi provided by 18-8 stainless steel, ensuring durability and long-term fastening integrity under heavy loads.
• Easy installation and removal with a Phillips No. 1 drive and coarse UNC threads, allowing for quick assembly while maintaining a Class 2A fit for precision.
• Corrosion-resistant construction with passivated 18-8 stainless steel, ideal for harsh industrial settings and extending service life.
• Compliance with rigorous standards including MIL-DTL-18240, RoHS 3, and REACH, ensuring quality and safety for critical applications.
• Versatile rounded pan head design that offers a low profile and smooth finish, minimizing snagging and enhancing aesthetics in assembled products.

Professional Applications & Engineering Value

This 4-40 UNC coarse thread rounded head screw is engineered to address common industrial challenges such as fluid leakage, vibration-induced loosening, and corrosion in harsh environments. Made from 18-8 stainless steel with a passivated finish, it resists oxidation and wear, while the integrated nylon patch thread locker and silicone rubber O-ring provide dual sealing and locking capabilities. This combination effectively prevents loosening under dynamic loads and seals against high-pressure fluids (up to 6000 psi), making it ideal for applications in aerospace, automotive, and machinery where reliability is critical. The Phillips drive and fully threaded design ensure easy installation and consistent performance, reducing downtime and enhancing operational efficiency in industrial sealing and fastening systems.

Specification Summary & Compliance

This screw features a 4-40 UNC coarse thread with a Class 2A fit for precise dimensional accuracy, ensuring reliable engagement in threaded holes. It is manufactured in compliance with MIL-DTL-18240 standards (including MS3212-1L, NASM3212, and NASM82496) and is RoHS 3 (2015/863/EU) Compliant and REACH (EC 1907/2006) Compliant, meeting environmental and safety regulations for global industrial use.