S-90273A430 1/4"-28 x 5/8" ASME B18.6.3 Steel Phillips Flat Head Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with zinc-plated steel construction, ensuring long-term reliability in harsh industrial environments.
• High tensile strength of 60,000 psi provides exceptional load-bearing capacity for demanding applications.
• Precision Class 2A thread fit guarantees smooth installation and secure fastening with minimal risk of cross-threading.
• Fully threaded design maximizes grip and distribution of clamping force along the entire length.
• Standard 82° countersink angle allows for a flush, professional finish in countersunk holes.
• Phillips drive (No. 4 size) offers widespread tool compatibility and efficient installation.
• Compliance with ASME B18.6.3, RoHS 3, and REACH ensures adherence to industry standards and environmental regulations.

Professional Applications & Engineering Value

This 1/4"-28 UNF flat head screw is engineered to address critical challenges in industrial assembly, such as vibration resistance and material fatigue. The zinc-plated steel provides a durable barrier against corrosion, extending service life in machinery, automotive, and outdoor equipment. The fine UNF thread and Class 2A fit deliver precise engagement, reducing the risk of loosening under dynamic loads. With a Rockwell B70 hardness and 60,000 psi tensile strength, it withstands high-stress conditions without deformation. The flat head with Phillips drive ensures a clean, recessed installation, ideal for applications where a smooth surface is essential, such as in enclosures or structural frameworks.

Specification Summary & Compliance

This fastener features a 1/4"-28 UNF fine thread with Class 2A thread fit for precise dimensional accuracy. It is manufactured in accordance with ASME B18.6.3 specifications and complies with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring environmental safety and industry-standard performance.