S-91257A915 7/8"-9 x 3 1/2" 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 for reliable performance in high-stress applications
• Superior corrosion resistance through zinc yellow-chromate plating that extends service life in harsh environments
• Optimized thread engagement with UNC coarse threading and Class 2A fit ensures secure fastening and vibration resistance
• Enhanced durability from Rockwell C33 hardness that maintains structural integrity under repeated stress
• Easy installation and removal with external hex drive design that accommodates standard tools
• Versatile partial threading allows for both clamping and alignment functions in assembly operations
• Industry-standard compliance meeting ASME B18.2.1 and SAE J429 specifications for quality assurance

Professional Applications & Engineering Value

Engineered for demanding industrial environments, these Grade 8 hex head screws deliver critical performance where failure is not an option. The 7/8"-9 UNC coarse thread configuration provides superior resistance to vibration loosening in heavy machinery, construction equipment, and structural assemblies. The zinc yellow-chromate plating creates a protective barrier against corrosion in outdoor or chemically aggressive settings, significantly extending maintenance intervals. With partial threading and 3½" length, these fasteners offer precise clamping force control while the external hex drive ensures compatibility with standard industrial tools. The combination of 150,000 PSI tensile strength and Rockwell C33 hardness makes these screws ideal for critical connections in manufacturing, infrastructure, and heavy equipment applications where reliability and safety are paramount.

Specification Summary & Compliance

These hex head screws feature precision Class 2A thread fit with 7/8"-9 UNC coarse threading and 2" minimum thread length. Manufactured to ASME B18.2.1 and SAE J429 Grade 8 specifications, ensuring dimensional accuracy and performance consistency. The fasteners are fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, making them suitable for global industrial applications with strict material restrictions.