S-90585A560 1/4"-28 x 1/2" ASME B18.3 Stainless Steel Hex Drive Flat Head Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with 316 Stainless Steel and passivated finish, ideal for harsh environments and extended service life.
• Exceptional thread reliability with a Class 3A fit, ensuring precise, secure connections and reducing the risk of cross-threading.
• High mechanical strength offering 70,000 psi tensile strength and Rockwell B55 hardness for demanding applications.
• Efficient installation and flush finish provided by the standard 82° countersink angle and 5/32" hex drive.
• Maximum grip and holding power from the fully threaded design along the entire 1/2" length.
• Guaranteed dimensional consistency and interchangeability, manufactured to meet ASME B18.3 specifications.
• Compliance with global environmental regulations including RoHS 3 and REACH, ensuring safe and sustainable use.

Professional Applications & Engineering Value

This 1/4"-28 UNF Flat Head Screw is engineered to solve critical challenges in industrial assembly. The 316 Stainless Steel construction and passivated finish provide outstanding resistance to chemicals, saltwater, and other corrosive agents, making it a top choice for marine, chemical processing, and food-grade equipment. The fine thread spacing and Class 3A thread fit deliver superior vibration resistance and clamping force in precision machinery, aerospace components, and high-stress structural applications. Its flat head with an 82° countersink ensures a smooth, flush surface, preventing snagging and improving aerodynamic or aesthetic profiles. The combination of 70,000 psi tensile strength and a hex drive allows for high-torque installation without stripping, enhancing assembly speed and long-term joint integrity.

Specification Summary & Compliance

This fastener adheres to ASME B18.3 dimensional standards, featuring a 1/4"-28 UNF thread with a precision Class 3A fit for tight tolerances. The screw is fully threaded with a length of 1/2", a head diameter of 0.531", and is manufactured from 316 Stainless Steel with a passivated surface treatment. It is compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring it is free from hazardous substances and safe for various industrial and export markets.