S-91257A889 3/4"-16 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 industrial applications, reducing the risk of fastener failure.
- Superior corrosion resistance from the zinc yellow-chromate plating extends service life in harsh environments, minimizing maintenance needs.
- High hardness rating (Rockwell C33) provides excellent wear resistance and durability under repetitive loading conditions.
- Fine UNF thread design offers superior vibration resistance and precise clamping force compared to coarse threads.
- Partially threaded shank allows for optimal grip and stress distribution, preventing loosening in dynamic applications.
- External hex drive design enables easy installation and removal with standard tools, saving time during assembly and maintenance.
- Grade 8 classification guarantees consistent quality and mechanical properties for critical fastening requirements.
Professional Applications & Engineering Value
This Grade 8 heavy-duty hex head screw delivers exceptional engineering value in demanding applications where failure is not an option. The 3/4"-16 UNF fine thread configuration provides superior resistance to vibration loosening in machinery, construction equipment, and structural assemblies. Manufactured from high-strength steel with Rockwell C33 hardness, it maintains integrity under extreme loads while the zinc yellow-chromate plating protects against corrosion in outdoor or chemically aggressive environments. The partially threaded design concentrates clamping force precisely where needed, making it ideal for securing heavy components in manufacturing, transportation, and infrastructure projects where reliability and longevity are paramount.
Specification Summary & Compliance
This fastener features Class 2A thread fit for consistent assembly compatibility and meets ASME B18.2.1 and SAE J429 specifications for dimensional accuracy and mechanical properties. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, ensuring safe usage across various industrial sectors.
