S-91864A061 1/4"-20 x 5/16" 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.
• Superior corrosion resistance from the black-oxide finish on alloy steel, extending service life in demanding industrial environments.
• Precise Class 3A thread fit provides tighter tolerances for secure, vibration-resistant assemblies with minimal backlash.
• Hex socket drive design allows for high torque application and easy installation in confined spaces with standard tools.
• Coarse UNC threading enables quick assembly and disassembly, improving maintenance efficiency and reducing downtime.
• Full threading along the 5/16" length offers consistent grip and load distribution across the entire fastener.
• Rockwell C37 hardness maintains structural integrity and resistance to wear over repeated use cycles.

Professional Applications & Engineering Value

These black-oxide alloy steel socket head cap screws are engineered to address critical challenges in heavy-duty machinery, automotive assemblies, and precision equipment where vibration loosening and material fatigue are common concerns. The 1/4"-20 UNC coarse thread with Class 3A fit ensures secure fastening in high-vibration environments, while the hex drive design permits high torque installation without stripping. The alloy steel construction combined with black-oxide surface treatment provides excellent resistance to rust and corrosion, making these screws ideal for outdoor equipment, manufacturing fixtures, and aerospace components where durability and reliability are paramount. Their fully threaded configuration guarantees uniform stress distribution, preventing joint failure in dynamic load applications.

Specification Summary & Compliance

This socket head cap screw features precise Class 3A thread fit with 1/4"-20 UNC coarse threads and meets ASTM A574 manufacturing specifications for high-strength fasteners. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, ensuring safe use in global industrial markets. Dimensions include 5/16" length, 3/8" head diameter, and 3/16" hex drive size for standardized tool compatibility.