S-91247A888 7/8"-9 x 4" ASME B18.2.1, SAE J429 Medium-Strength Grade 5 Steel Hex Head Screws

Key Features & Benefits at a Glance

• Exceptional tensile strength of 120,000 psi ensures reliable performance in high-stress industrial applications, reducing the risk of fastener failure.
• Grade 5 classification and Rockwell C25 hardness provide superior durability and resistance to wear, extending service life in demanding environments.
• Zinc plating finish offers excellent corrosion resistance, protecting the steel material from rust and environmental damage.
• Coarse UNC threads with Class 2A fit enable quick and secure installation, minimizing cross-threading and ensuring consistent assembly quality.
• Partially threaded design allows for precise clamping force control, ideal for applications where unthreaded shank strength is critical.
• External hex drive and hex head facilitate easy tightening with standard tools, improving installation efficiency and reducing labor time.
• Compliance with ASME B18.2.1 and SAE J429 standards guarantees dimensional accuracy and interoperability, meeting rigorous engineering specifications.

Professional Applications & Engineering Value

This 7/8"-9 UNC Grade 5 hex head screw is engineered for heavy-duty industrial applications where reliability and strength are paramount. The zinc plated steel construction combats corrosion in harsh environments, while the coarse thread design ensures rapid assembly and robust holding power in materials like structural steel or machinery frames. With a partial threading and external hex drive, it provides optimal clamp load distribution and easy access for maintenance, reducing downtime in sectors such as construction, automotive, and equipment manufacturing. Its high tensile strength and Rockwell C25 hardness address common challenges like vibration loosening and mechanical stress, delivering long-term performance and safety in critical fastening joints.

Specification Summary & Compliance

This screw adheres to precise dimensional tolerances with a Class 2A thread fit and UNC thread type, ensuring consistent compatibility. It meets ASME B18.2.1 and SAE J429 specifications for quality and performance. Additionally, it is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, supporting environmentally responsible and safe industrial use.