S-92805A270 4-40 x 3/16" 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 from -70° to 250°F, preventing loosening in dynamic environments
• Superior corrosion resistance from 18-8 stainless steel construction ensures long-term reliability in harsh industrial conditions
• High-strength performance with 70,000 psi tensile strength and Rockwell B55 hardness withstands heavy mechanical stresses
• Precision Class 3A thread fit provides consistent engagement and reliable assembly in critical applications
• Secure hex drive design with 1/16" drive size enables positive torque transmission and prevents cam-out during installation
• Optimized flat head profile with 82° countersink angle allows for flush mounting in precision assemblies
• Full threading along the 3/16" length ensures maximum engagement and holding power in thin materials

Professional Applications & Engineering Value

These 4-40 UNC flat head screws deliver exceptional engineering value in applications where vibration resistance, corrosion protection, and precise flush mounting are critical. The 18-8 stainless steel construction combined with the nylon patch thread locker addresses common industrial challenges of fastener loosening under thermal cycling and exposure to corrosive elements. The coarse UNC thread pattern and Class 3A thread fit ensure rapid assembly with minimal cross-threading risk, while the hex drive design provides superior torque transmission compared to slotted alternatives. Ideal for electronics enclosures, aerospace components, and precision machinery where MIL-DTL-18240 compliance is required, these screws maintain integrity across extreme temperature ranges from -70° to 250°F.

Specification Summary & Compliance

This 4-40 UNC flat head screw features precision Class 3A thread tolerances with coarse thread spacing and right-hand threading. Manufactured to meet MIL-DTL-18240 specifications with complete RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) compliance. The fastener maintains dimensional accuracy with 0.255" head diameter, 3/16" length, and standard 82° flat head profile. Quality assurance includes verification of 70,000 psi tensile strength and proper nylon patch thread locker application for consistent performance in regulated industrial applications.