S-91274A177 1/4"-28 x 3/8" ASME B18.3, ASTM A574, ASTM B117 Alloy Steel Socket Head Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with zinc-flake coating, ideal for harsh industrial environments and extending service life.
• Exceptional tensile strength of 170,000 psi ensures reliable performance under high-stress conditions, preventing fastener failure.
• Precise Class 3A thread fit guarantees secure, vibration-resistant assemblies with minimal risk of loosening.
• High hardness (Rockwell C37) provides excellent wear resistance and durability for repeated use.
• Fine UNF thread design offers improved adjustment accuracy and a tighter seal compared to coarse threads.
• Standard hex socket drive (3/16") allows for high-torque installation with common tools, simplifying assembly.
• Full compliance with major standards including ASME B18.3, ASTM A574, and ASTM B117, ensuring consistent quality and reliability.

Professional Applications & Engineering Value

This 1/4"-28 UNF Socket Head Cap Screw is engineered to address critical challenges in demanding applications such as heavy machinery, automotive assemblies, and precision equipment. The zinc-flake-coated alloy steel construction provides a robust barrier against corrosion, significantly reducing maintenance needs in environments exposed to moisture and chemicals. Its Class 3A fine thread fit ensures superior clamping force and vibration resistance, which is essential for dynamic loads and high-integrity joints. The combination of 170,000 psi tensile strength and Rockwell C37 hardness makes it suitable for high-stress points where fastener integrity is non-negotiable. By utilizing a fully threaded design and 3/16" hex drive, this screw facilitates efficient installation and offers consistent performance across various industrial fastening tasks, enhancing overall assembly reliability.

Specification Summary & Compliance

This socket head cap screw adheres to precise dimensional standards, featuring a Class 3A thread fit for high accuracy and a UNF fine thread with a size of 1/4"-28. It is manufactured in compliance with ASME B18.3, ASTM A574 for material consistency, and ASTM B117 for corrosion testing. Additionally, the product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring it meets environmental and safety standards for industrial use.