S-91385A174 1/2"-20 x 1 1/4" ASME B18.3, ASTM F912 Set Screws

Key Features & Benefits at a Glance

• Vibration-resistant locking with permanent nylon patch thread locker that maintains secure fastening in high-stress environments
• Superior corrosion protection through black-oxide coating on alloy steel, extending service life in demanding industrial conditions
• Precise thread engagement with UNF Class 3A fine threads ensuring tight tolerances and reliable performance in critical assemblies
• High-strength construction with Rockwell C45 hardness providing exceptional durability and resistance to wear
• Wide temperature compatibility from -50°F to 250°F, making it suitable for diverse operating environments
• Space-saving design with headless configuration and 1/4" hex drive for applications with limited clearance
• Cup tip design that creates positive seating and prevents slipping on shaft surfaces

Professional Applications & Engineering Value

This black-oxide alloy steel set screw delivers exceptional performance in demanding industrial applications where vibration resistance and precise positioning are critical. The permanent nylon patch thread locker eliminates the need for additional locking compounds while providing reliable anti-loosening properties in machinery, automotive, and aerospace assemblies. Engineered with UNF Class 3A fine threads, this fastener ensures superior clamping force and precise alignment in high-tolerance applications. The headless design with 1/4" hex drive allows for installation in confined spaces while maintaining high torque capability. The combination of Rockwell C45 hardness and temperature-resistant locking technology makes this set screw ideal for permanent fastening solutions in rotating equipment, gear assemblies, and precision instruments where reliability cannot be compromised.

Specification Summary & Compliance

This 1/2"-20 UNF set screw features Class 3A thread fit for precision applications and meets ASME B18.3 standards (ASTM F912). The manufacturing process ensures compliance with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations. The right-hand fine threads provide optimal engagement while the cup tip design ensures positive contact with mating surfaces. The product maintains dimensional accuracy according to industrial specifications for reliable performance across various applications.