S-91257A823 5/8"-11 x 8 1/2" ASME B18.2.1, SAE J429 High-Strength Grade 8 Steel Hex Head Screws
High-Strength Grade 8 Steel Hex Head Screws
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Basic Information
Head Parameters
Dimensions
Thread Parameters
Tip & Drive Parameters
Material & Strength
Temperature & Environment
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Key Features & Benefits at a Glance
- Exceptional tensile strength of 150,000 PSI ensures reliable performance in high-stress applications, reducing the risk of fastener failure.
- Superior corrosion resistance from the zinc yellow-chromate plating extends service life in harsh or outdoor environments.
- High hardness rating (Rockwell C33) provides excellent wear resistance and durability under repeated loads.
- Coarse UNC threading allows for faster installation and better grip in a variety of materials, improving assembly efficiency.
- Partially threaded design offers optimal clamping force and vibration resistance where full threading isn't required.
- Class 2A thread fit ensures consistent, reliable engagement with standard nuts and tapped holes, minimizing cross-threading risks.
- External hex drive enables high-torque installation with common tools, facilitating quick and secure fastening.
Professional Applications & Engineering Value
This Grade 8 hex head screw is engineered to address critical challenges in heavy machinery, construction, and structural assemblies where high tensile strength and corrosion resistance are paramount. The steel material combined with zinc yellow-chromate plating provides a robust barrier against environmental degradation, making it ideal for outdoor or corrosive settings. The coarse UNC thread ensures reliable performance in wood, metal, and composite materials, reducing stripping and improving load distribution. With a partial thread design, it delivers superior clamping in dynamic applications, preventing loosening under vibration. These features make it a trusted choice for engineers requiring durable, compliant fasteners that meet rigorous industrial standards.
Specification Summary & Compliance
This fastener adheres to Class 2A thread fit for consistent dimensional accuracy and is manufactured in accordance with ASME B18.2.1 and SAE J429 specifications. It is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring environmental and safety standards are met for industrial use.
