S-91385A158 1/4"-28 x 3/16" ASME B18.3, ASTM F912 Set Screws

Key Features & Benefits at a Glance

• Permanent vibration resistance with nylon patch thread locker that maintains secure fastening in high-vibration environments
• Superior corrosion protection through black-oxide coating on alloy steel, extending service life in demanding conditions
• Precise thread engagement with Class 3A fit ensuring tight tolerances and reliable assembly in critical applications
• High-strength performance from Rockwell C45 hardness rating, providing excellent resistance to wear and deformation
• Wide temperature compatibility with thread locker functioning from -50°F to 250°F for diverse operating environments
• Secure component positioning through cup point design that creates positive seating and prevents slippage
• Space-saving installation with headless configuration ideal for confined spaces and flush mounting requirements

Professional Applications & Engineering Value

This black-oxide alloy steel set screw delivers exceptional engineering value in industrial applications where vibration resistance and precise component positioning are critical. The UNF fine thread spacing combined with Class 3A thread fit ensures superior engagement in machinery, automotive assemblies, and precision equipment. The nylon patch locking technology provides permanent anti-loosening protection without compromising the high-temperature performance up to 250°F. The cup point design bites securely into mating surfaces, preventing rotational movement in pulleys, gears, and collars. Engineered for headless installation with hex drive convenience, this fastener solves common challenges in space-constrained assemblies while maintaining Rockwell C45 hardness for long-term reliability.

Specification Summary & Compliance

This set screw features 1/4"-28 UNF fine threads with Class 3A thread fit for precision assembly. Manufactured to ASME B18.3 specifications with Rockwell C45 hardness rating. The product is fully RoHS 3 (2015/863/EU) compliant and REACH (EC 1907/2006) compliant, meeting international environmental standards. The nylon patch thread locker maintains effectiveness across an operational temperature range of -50°F to 250°F, ensuring reliable performance in diverse industrial conditions.