S-93802A425 4-40 x 3/8" MIL-DTL-18240, MS3212-3L, NASM3212, NASM82496 Sealing Thread-Locking Stainless Steel Pan Head Phillips Screws

Key Features & Benefits at a Glance

• Superior sealing performance with integrated silicone O-ring, preventing leaks in high-pressure environments up to 6000 psi
• Reliable vibration resistance through Nylon Patch thread locker, maintaining secure fastening in dynamic applications
• Exceptional corrosion resistance with 18-8 stainless steel construction and passivated finish for long-term durability
• Wide temperature compatibility from -40° to 400° F, ensuring performance stability across diverse operating conditions
• High tensile strength of 70,000 psi provides robust mechanical integrity for demanding applications
• Easy installation and removal with Phillips drive and standard pan head design for efficient maintenance
• Precise thread engagement with Class 2A UNC coarse threads ensuring consistent, reliable fastening

Professional Applications & Engineering Value

These 4-40 UNC rounded head screws deliver critical engineering solutions where sealing reliability and vibration resistance are paramount. The combination of 18-8 stainless steel material with passivated finish provides exceptional corrosion protection in harsh environments, while the integrated silicone rubber O-ring and Nylon Patch locking system create a dual-sealing mechanism that prevents fluid ingress and maintains pressure integrity up to 6000 psi. The coarse UNC threading with Class 2A fit ensures quick installation and reliable performance in aerospace, industrial machinery, and heavy-duty equipment where consistent fastening under vibration is essential. The fully threaded design maximizes engagement strength, making these fasteners ideal for critical assemblies requiring both mechanical security and environmental sealing.

Specification Summary & Compliance

This 4-40 UNC 3/8" rounded head screw features precise Class 2A thread fit with coarse UNC threading and right-hand direction. Manufacturing and performance comply with MIL-DTL-18240, MS3212-3L, NASM3212, and NASM82496 specifications. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, ensuring safe use across global markets. The combination of standardized dimensions and certified materials guarantees consistent performance and interchangeability in regulated applications.