S-91385A355 1/4"-28 x 1/2" ASME B18.3, ASTM F912 Set Screws

Key Features & Benefits at a Glance

• Vibration-resistant locking with the integrated Nylon Patch prevents loosening under dynamic loads, ensuring reliable long-term fastening.
• Exceptional durability from Rockwell C45 hardness and Black-Oxide Alloy Steel construction provides superior resistance to wear and corrosion in harsh environments.
• Precise, secure fit guaranteed by the Class 3A UNF fine thread, offering high clamping force and reduced risk of stripping in critical assemblies.
• Wide temperature tolerance of the locking element from -50°F to 250°F maintains performance in both extreme cold and high-heat applications.
• Space-saving headless design with a 1/8" Hex Drive allows for installation in confined spaces and provides a flush, unobtrusive finish.
• Enhanced grip and minimal surface damage from the Cup Tip, which concentrates holding force for secure positioning of components on shafts or hubs.
• Guaranteed quality and safety through compliance with ASME B18.3, ASTM F912, RoHS 3, and REACH, ensuring material consistency and environmental responsibility.

Professional Applications & Engineering Value

This 1/4"-28 x 1/2" UNF Set Screw is engineered to solve common industrial challenges such as component slippage and fastener failure in high-vibration machinery. The Black-Oxide Alloy Steel material, combined with a Rockwell C45 hardness, delivers a robust solution that withstands mechanical stress and resists corrosion, extending service life in demanding settings like automotive assemblies, precision tooling, and conveyor systems. The Nylon Patch Locking feature is critical for maintaining clamp load without the need for additional lock washers, making it ideal for right-hand thread applications where reliability is non-negotiable. Its fine thread and cup tip design ensure maximum contact and holding power on shafts, pulleys, and gears, reducing maintenance downtime and improving overall system integrity.

Specification Summary & Compliance

This set screw adheres to precise dimensional standards with a Class 3A thread fit and UNF fine thread specification, ensuring tight tolerances for secure fastening. It is manufactured in compliance with ASME B18.3 and ASTM F912 specifications, guaranteeing consistent quality and performance. The product is also RoHS 3 (2015/863/EU) Compliant and REACH (EC 1907/2006) Compliant, confirming it meets stringent environmental and safety regulations for hazardous substances.