S-91251A409 1 1/4"-12 x 6 1/2" ASTM A574 Alloy Steel Socket Head Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with black-oxide coating, extending service life in harsh industrial environments.
• Exceptional tensile strength of 170,000 psi ensures reliable performance under high-stress applications.
• Precise Class 2A thread fit guarantees smooth assembly and secure fastening with minimal play.
• Fine UNF thread spacing provides enhanced vibration resistance and improved load distribution.
• Partially threaded design allows for optimal clamping force control in specific assembly setups.
• Hardened to Rockwell C37 for excellent wear resistance and durability in repetitive use.
• Large 7/8" hex drive enables high-torque installation with standard tools, reducing assembly time.

Professional Applications & Engineering Value

This black-oxide alloy steel socket head cap screw is engineered to address critical challenges in heavy machinery, automotive, and construction sectors. The 1 1/4"-12 UNF fine threads and Class 2A fit ensure precise alignment and resistance to loosening under dynamic loads, while the partially threaded rod type allows engineers to concentrate clamping force exactly where needed. The 170,000 psi tensile strength and Rockwell C37 hardness make it ideal for high-stress joints, preventing failure in demanding applications. Its black-oxide surface treatment provides a durable barrier against rust and corrosion, extending maintenance intervals in outdoor or chemically aggressive environments.

Specification Summary & Compliance

This socket head cap screw adheres to ASTM A574 manufacturing standards, ensuring consistent quality and performance. Thread specifications include 1 1/4"-12 UNF fine threads with Class 2A fit for precise dimensional accuracy. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, confirming its suitability for global industrial use without hazardous substances.