S-91257A925 7/8"-9 x 6" ASME B18.2.1, SAE J429 High-Strength Grade 8 Steel Hex Head Screws

Key Features & Benefits at a Glance

• Exceptional Load-Bearing Capacity – With 150,000 psi tensile strength and Rockwell C33 hardness, this screw withstands extreme mechanical stress, reducing failure risks in critical assemblies.
• Superior Corrosion Resistance – The zinc yellow-chromate plating provides a durable barrier against rust and environmental degradation, extending service life in harsh conditions.
• Reliable Thread Engagement – Coarse UNC threads with Class 2A fit ensure easy installation and secure fastening, minimizing cross-threading and improving assembly efficiency.
• Optimized for High-Torque Applications – The external hex head design (1 5/16" width) allows for high torque application with standard tools, enhancing grip and stability during tightening.
• Partial Threading for Precision Fastening – The 2" minimum thread length on a 6" shank provides unthreaded grip areas, ideal for applications requiring clamping force without full-length threading.
• Industry-Standard Compliance – Meets ASME B18.2.1 and SAE J429 specifications, ensuring interchangeability and performance reliability in regulated industrial environments.
• Environmental and Safety Assurance – RoHS 3 and REACH compliance guarantees the screw is free from hazardous substances, supporting sustainable and safe manufacturing practices.

Professional Applications & Engineering Value

Engineered for heavy-duty industrial applications, this Grade 8 hex head screw addresses common challenges in construction, machinery, and structural assemblies where high tensile strength and corrosion resistance are critical. The 7/8"-9 UNC coarse thread design facilitates quick installation in tough materials, while the zinc yellow-chromate plating prevents oxidation in outdoor or humid environments, reducing maintenance costs. Its partial threading allows precise load distribution, making it suitable for bolted joints requiring controlled clamping force. By conforming to ASME B18.2.1 standards, it ensures compatibility with existing systems, minimizing downtime and enhancing operational efficiency in sectors like automotive, aerospace, and heavy equipment manufacturing.

Specification Summary & Compliance

This screw features a Class 2A thread fit for consistent dimensional accuracy and smooth assembly, with UNC coarse threads (7/8"-9) and a 6" length including a 2" minimum thread length. Manufactured to ASME B18.2.1 and SAE J429 specifications, it guarantees mechanical performance and interoperability. Compliance with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) ensures adherence to environmental and safety regulations, supporting global supply chain requirements.