S-91251A425 6-40 x 7/8" ASTM A574 Alloy Steel Socket Head Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with black-oxide coating, extending service life in demanding industrial environments.
• Exceptional tensile strength of 170,000 psi ensures reliable performance under high-stress conditions.
• Precise Class 3A thread fit guarantees secure, vibration-resistant assemblies with minimal risk of loosening.
• Fine UNF thread profile provides improved load distribution and superior holding power in fine-pitch applications.
• Hardened alloy steel construction (Rockwell C37) offers excellent wear resistance and durability.
• Hex socket drive design allows for high-torque installation and removal in confined spaces.
• Full thread coverage along the 7/8" length enables flexible positioning and consistent clamping force.

Professional Applications & Engineering Value

Engineered for precision assembly, this black-oxide alloy steel socket head cap screw addresses critical challenges in industrial fastening. The 6-40 UNF fine thread and Class 3A fit deliver superior resistance to vibrational loosening, making it ideal for machinery, automotive components, and precision equipment where reliability is paramount. The 170,000 psi tensile strength and Rockwell C37 hardness ensure the fastener maintains integrity under extreme loads, while the black-oxide surface treatment provides a durable barrier against rust and corrosion. Its hex socket drive facilitates secure installation in tight spaces, reducing assembly time and improving maintenance efficiency in high-performance engineering applications.

Specification Summary & Compliance

This socket head cap screw features a 6-40 UNF fine thread with Class 3A precision fit and a length of 7/8 inch. It is manufactured in compliance with ASTM A574 specifications for high-strength alloy steel fasteners and meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental standards, ensuring safety and regulatory adherence for global industrial use.