S-91257A891 3/4"-16 x 9 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 load-bearing capacity with 150,000 psi tensile strength for reliable performance in high-stress applications.
- Superior corrosion resistance provided by zinc yellow-chromate plating, extending service life in harsh environments.
- High-strength Grade 8 steel construction with Rockwell C33 hardness to resist wear and deformation under heavy loads.
- Precise Class 2A thread fit and 3/4"-16 UNF fine threading for secure, vibration-resistant fastening in critical assemblies.
- Partially threaded design allows for optimal clamping force distribution and easier alignment in structural connections.
- External hex drive and 1 1/8" head width enable high-torque installation with standard tools, reducing assembly time.
- Full compliance with ASME, SAE, RoHS 3, and REACH standards ensures material safety and interoperability in regulated industries.
Professional Applications & Engineering Value
This Grade 8 hex head screw is engineered to address critical challenges in heavy machinery, construction, and industrial equipment where joint integrity is paramount. The high-strength steel and Rockwell C33 hardness prevent stripping and shear failure under dynamic loads, while the zinc yellow-chromate plating resists oxidation in humid or chemical-exposed environments. The 3/4"-16 UNF fine thread and Class 2A fit maintain tight tolerances in vibrating systems, reducing maintenance downtime. Ideal for bolting flanges, structural frames, and heavy-duty assemblies, it delivers long-term reliability where standard fasteners fall short.
Specification Summary & Compliance
This fastener adheres to Class 2A thread fit per ASME B18.2.1 and SAE J429 Grade 8 specifications, ensuring dimensional accuracy and interchangeability. The 3/4"-16 UNF fine thread with a minimum 2" thread length provides consistent engagement, while the 9 1/2" length accommodates thick sections. It is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, guaranteeing the absence of restricted hazardous substances for safe industrial use.
