S-91253A958 5/8"-18 x 4" ASTM F835 Alloy Steel Hex Drive Flat Head Screws

Key Features & Benefits at a Glance

• Exceptional tensile strength of 130,000 PSI ensures reliable performance in high-stress industrial applications, reducing the risk of fastener failure.
• Class 3A thread fit provides superior precision and tight tolerances for secure, vibration-resistant assemblies in critical machinery.
• Alloy steel construction with Rockwell C37 hardness offers excellent durability and resistance to wear, extending service life in demanding environments.
• 82° countersink angle and standard flat head profile allow for a flush, clean finish, minimizing protrusion and improving safety in assembled products.
• 3/8" hex drive design enables easy installation and high torque application, speeding up assembly processes and reducing labor time.
• Partial threading provides optimal grip and clamping force where needed, enhancing joint integrity without unnecessary thread engagement.
• Compliance with ASTM F835, RoHS 3, and REACH ensures adherence to strict industry standards and environmental regulations, supporting sustainable and safe usage.

Professional Applications & Engineering Value

This 5/8"-18 UNF alloy steel flat head screw is engineered to address common industrial challenges such as vibration loosening and material fatigue. The fine UNF thread and Class 3A fit deliver precise engagement, crucial for machinery and equipment where alignment and stability are paramount. Made from high-grade alloy steel and hardened to Rockwell C37, it resists deformation under heavy loads, making it ideal for construction, automotive, and heavy machinery applications. The 82° countersink angle ensures a seamless fit in pre-drilled holes, reducing stress concentrations and improving aerodynamic or aesthetic profiles. With a 3/8" hex drive, installation is efficient even in confined spaces, supporting faster project completion and reduced maintenance needs in industrial screw assemblies.

Specification Summary & Compliance

This product features a 5/8"-18 UNF thread with Class 3A thread fit for high precision, and a length of 4 inches with partial threading. It meets ASTM F835 specifications for consistent quality and performance. Additionally, it is compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring environmental safety and regulatory adherence in global supply chains.