S-91251A309 7/8"-14 x 3" ASTM A574 Alloy Steel Socket Head Screws

Key Features & Benefits at a Glance

• Exceptional tensile strength of 170,000 psi ensures reliable performance under extreme loads and prevents fastener failure in demanding applications.
• Superior wear resistance from Rockwell C37 hardness provides long-lasting durability and maintains thread integrity through repeated use.
• Precision Class 3A thread fit guarantees secure, vibration-resistant connections with minimal play for enhanced assembly reliability.
• Corrosion-resistant black-oxide finish on alloy steel offers improved protection against rust in harsh industrial environments.
• High-torque 3/4" hex drive allows for easy installation and removal with standard tools, reducing assembly time and effort.
• Fully threaded UNRF fine thread design ensures maximum grip length and superior clamping force distribution across the entire fastener.
• Compliance with ASTM A574 certifies consistent quality and mechanical properties for critical engineering applications.

Professional Applications & Engineering Value

These black-oxide alloy steel socket head cap screws deliver critical performance where high strength and precision are non-negotiable. The UNRF fine thread with Class 3A fit provides exceptional resistance to vibrational loosening in heavy machinery, automotive assemblies, and precision equipment. The combination of 170,000 psi tensile strength and Rockwell C37 hardness ensures these fasteners withstand severe dynamic loads without stripping or shearing. The 3/4" hex drive accommodates high installation torque, making them ideal for compact spaces where wrench clearance is limited. Engineered to meet ASTM A574 specifications, they offer reliable solutions for manufacturing, construction, and industrial maintenance applications requiring durable, high-performance fastening.

Specification Summary & Compliance

This socket head cap screw features precision 7/8"-14 UNRF fine threads with Class 3A fit for exacting tolerance requirements. Manufacturing complies with ASTM A574 specification for high-strength alloy steel socket head cap screws. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, ensuring safe use in industrial applications worldwide.