S-91205A110 4-40 x 1/2" ASME B18.3, ASTM A574 Alloy Steel Thread-Locking Socket Head Screws

Key Features & Benefits at a Glance

• Permanent vibration resistance with Nylon Patch thread locker that maintains secure locking from -70° to 250°F
• Exceptional tensile strength of 170,000 psi ensures reliable performance under high-stress industrial applications
• Superior thread precision with Class 3A fit provides consistent engagement and reduced risk of cross-threading
• Enhanced corrosion protection through Black-Oxide coating on Alloy Steel, extending service life in demanding environments
• Optimized drive engagement with standard hex socket and 3/32" drive size for secure tooling and reduced cam-out
• Broad regulatory compliance including RoHS 3 and REACH, ensuring safe use in global markets
• Robust material properties with Rockwell C37 hardness offering excellent wear resistance and durability

Professional Applications & Engineering Value

These 4-40 UNC Socket Head Cap Screws with Nylon Patch locking address critical vibration-induced loosening in precision assemblies. Manufactured from Black-Oxide Alloy Steel, they provide reliable permanent locking across extreme temperature ranges (-70° to 250°F), making them ideal for automotive, aerospace, and industrial machinery where thermal cycling occurs. The Class 3A thread fit ensures precise engagement in coarse UNC threads, reducing installation torque variations while the fully threaded design maximizes clamping force distribution. These hex drive socket screws deliver consistent performance in high-vibration environments where fastener integrity is paramount.

Specification Summary & Compliance

Manufactured to ASME B18.3 specifications with material compliance to ASTM A574. Features Class 3A thread fit for precision UNC coarse threading. Fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations. Standard socket head profile with right-hand thread direction and fully threaded design.