S-90128A318 1/4"-20 x 9/16" ASME B18.3, ASTM A574 Alloy Steel Socket Head Screws

Key Features & Benefits at a Glance

• Exceptional tensile strength of 170,000 PSI ensures reliable performance under high-stress conditions, reducing the risk of fastener failure in demanding applications.
• Superior corrosion resistance from zinc plating protects against rust and extends service life in harsh industrial environments.
• Precise Class 3A thread fit provides tighter tolerances for secure, vibration-resistant assemblies, minimizing loosening over time.
• High hardness (Rockwell C37) offers excellent wear resistance, maintaining thread integrity through repeated use and installation.
• Hex drive compatibility allows for easy installation and removal with standard tools, improving assembly efficiency and reducing labor time.
• Full threading ensures consistent engagement along the entire length, providing uniform clamping force and stability in assembled components.
• Compliance with major standards including ASME B18.3 and ASTM A574 guarantees consistent quality and interoperability in regulated industries.

Professional Applications & Engineering Value

This 1/4"-20 UNC Socket Head Cap Screw is engineered to address critical challenges in industrial fastening, where vibration, high loads, and environmental factors can compromise joint integrity. The zinc-plated alloy steel construction combats corrosion in machinery, automotive, and outdoor equipment, while the coarse UNC thread facilitates quick assembly and resists cross-threading. Its socket head design with hex drive is ideal for confined spaces, allowing secure torque application without slippage. By combining 170,000 PSI tensile strength with Class 3A thread precision, it delivers reliable performance in heavy-duty applications such as manufacturing fixtures, construction equipment, and precision engineering assemblies, ensuring long-term durability and reduced maintenance costs.

Specification Summary & Compliance

This screw features a 1/4"-20 UNC coarse thread with Class 3A fit for high precision, and dimensions include a 9/16" length, 3/8" head diameter, and 1/4" head height. It meets ASME B18.3 and ASTM A574 specifications for manufacturing consistency, and is compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, ensuring safe use in global markets.