S-91255A034 5/16"-18 x 1 3/8" ASTM F835 Steel Button Head Hex-Drive Screws

Key Features & Benefits at a Glance

• Exceptional corrosion resistance with black-oxide coating, extending service life in harsh industrial environments.
• Superior tensile strength of 120,000 psi ensures reliable performance under high-stress conditions without failure.
• Precise Class 3A thread fit provides tighter tolerances for secure, vibration-resistant assemblies.
• Fully threaded coarse UNC design offers faster installation and enhanced grip in various materials.
• Rockwell C39 hardness rating delivers excellent wear resistance and durability for long-term use.
• Hex drive (3/16") with rounded button head allows for easy, tool-friendly installation and a low-profile finish.
• Compliance with ASME B18.3 and ASTM F835 guarantees consistent quality and interoperability in professional applications.

Professional Applications & Engineering Value

Engineered for demanding industrial settings, this 5/16"-18 UNC Class 3A black-oxide alloy steel rounded head screw addresses critical challenges like vibration loosening and material fatigue. The coarse thread and fully threaded construction ensure rapid, secure fastening in metals and composites, reducing assembly time while maintaining integrity. Its high tensile strength and Rockwell C39 hardness make it ideal for heavy machinery, automotive assemblies, and structural frameworks where reliability is paramount. The black-oxide surface treatment provides an added layer of protection against rust, extending component life in environments exposed to moisture or chemicals. By integrating hex drive functionality and standardized dimensions, this screw streamlines maintenance and replacement processes, supporting efficient B2B procurement and inventory management.

Specification Summary & Compliance

This product adheres to Class 3A thread fit per UNC standards, ensuring precise dimensional accuracy for secure fastening. It meets ASME B18.3 and ASTM F835 specifications for consistent performance and safety. Additionally, it is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, confirming environmental safety and regulatory alignment for global industrial use.