S-92210A423 1/4"-28 x 1 1/8" ASME B18.3 Stainless Steel Hex Drive Flat Head Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with 18-8 stainless steel construction and passivated finish, ideal for harsh industrial environments.
• Exceptional mechanical strength offering 70,000 psi tensile strength and Rockwell B55 hardness for reliable, long-term fastening under stress.
• Precision thread engagement with Class 3A fit and UNF fine thread spacing, ensuring secure, vibration-resistant connections.
• Optimized flush mounting featuring a standard 82° countersink angle and flat head design for seamless, aerodynamic surface finishes.
• Efficient installation and removal using a 5/32" hex drive, providing superior torque transmission and reduced tool slippage.
• Full threading along the 1 1/8" length for maximum grip and adjustability in a wide range of material thicknesses.
• Compliance with major industry standards including ASME B18.3, RoHS 3, and REACH, ensuring safety and regulatory acceptance.

Professional Applications & Engineering Value

This 1/4"-28 UNF flat head screw is engineered to address critical challenges in precision assembly and machinery. The 18-8 stainless steel material, enhanced by a passivated finish, provides excellent resistance to oxidation and chemical exposure, making it suitable for applications in marine, chemical processing, and food equipment where corrosion is a concern. The fine thread spacing and Class 3A thread fit deliver tight tolerances, reducing the risk of loosening under dynamic loads and vibration—common in automotive, aerospace, and electronic enclosures. Its fully threaded design and 82° countersink angle ensure a flush fit, minimizing protrusions in streamlined designs. These features make it a reliable choice for engineers seeking durability, compliance, and performance in demanding industrial applications.

Specification Summary & Compliance

This screw adheres to Class 3A thread fit tolerances per UNF standards, ensuring precise thread engagement. It is manufactured in compliance with ASME B18.3 specifications, guaranteeing dimensional accuracy and consistency. The product meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulatory requirements, confirming it is free from hazardous substances and safe for various industrial and international markets.