S-91253A621 3/8"-16 x 5/8" ASTM F835 Alloy Steel Hex Drive Flat Head Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with black-oxide coating on alloy steel, extending service life in demanding industrial environments.
• Exceptional mechanical strength with 130,000 psi tensile strength and Rockwell C39 hardness for reliable performance under high stress.
• Precise Class 3A thread fit ensures tighter tolerances and secure fastening, reducing the risk of loosening in critical assemblies.
• Fully threaded design provides maximum grip and load distribution along the entire length for enhanced joint integrity.
• Standard 82° countersink angle allows for a flush, low-profile finish, ideal for applications requiring smooth surfaces.
• Hex drive (7/32") compatibility enables easy installation and removal with common tools, improving assembly efficiency.
• Compliance with major standards including ASME B18.3 and ASTM F835, ensuring consistent quality and reliability for industrial use.

Professional Applications & Engineering Value

Engineered for demanding industrial settings, this 3/8"-16 UNC flat head screw in black-oxide alloy steel addresses common challenges like vibration-induced loosening and environmental wear. The Class 3A thread fit and coarse threading provide superior holding power in materials such as metal and hard plastics, while the fully threaded design ensures even stress distribution to prevent joint failure. With a right-hand thread direction and standard flat head profile, it integrates seamlessly into machinery, automotive assemblies, and structural frameworks, offering a reliable solution for applications requiring high tensile strength and durability under repetitive loads.

Specification Summary & Compliance

This screw adheres to precise dimensional standards, including Class 3A thread fit for tight tolerances and UNC coarse threading for efficient installation. It meets ASME B18.3 and ASTM F835 specifications, ensuring consistent performance in industrial fastening. Additionally, it is compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, supporting environmentally responsible and safe usage in global markets.