S-94066A857 1/4"-28 x 1/2" Tamper-Resistant Drilled Spanner Stainless Steel Pan 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.
• High tensile strength of 80,000 psi and Rockwell B96 hardness for reliable performance in demanding applications.
• Precise Class 2A thread fit ensures smooth assembly and secure fastening with minimal risk of cross-threading.
• Drilled spanner drive (No. 14) provides secure tool engagement and high torque capability without stripping.
• Fully threaded design offers consistent holding power along the entire 1/2" length for uniform load distribution.
• Compliance with RoHS 3 and REACH regulations guarantees environmental safety and unrestricted use in regulated industries.
• UNF fine thread (1/4"-28) delivers enhanced vibration resistance and superior clamping force in precision assemblies.

Professional Applications & Engineering Value

This 1/4"-28 UNF rounded head screw is engineered to address critical challenges in industrial fastening, where corrosion resistance and mechanical reliability are paramount. The 18-8 stainless steel material, combined with a passivated finish, provides exceptional protection against oxidation and chemical exposure, making it suitable for marine, chemical processing, and outdoor equipment. The drilled spanner drive ensures high torque transmission without cam-out, reducing installation time and tool wear. With its fine UNF threads and Class 2A fit, this screw maintains tight tolerances in vibrating environments, preventing loosening in machinery, automotive components, and electronic enclosures. Its fully threaded design maximizes grip in thin materials, offering versatile application across assembly lines while meeting stringent RoHS and REACH standards for global supply chain compliance.

Specification Summary & Compliance

This screw adheres to UNF thread standards with a Class 2A thread fit for precise dimensional accuracy. It is manufactured from 18-8 stainless steel with a passivated finish, featuring a rounded pan head, drilled spanner drive (No. 14), and right-hand fine threads. Key dimensions include a 1/4"-28 thread size, 1/2" length, 0.492" head diameter, and 0.144" head height. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring it meets environmental and safety requirements for industrial use.