S-91257A785 9/16"-18 x 4" ASME B18.2.1, SAE J429 High-Strength Grade 8 Steel Hex Head Screws
High-Strength Grade 8 Steel Hex Head Screws
Image may differ from product. See technical specification for details.
Basic Information
Head Parameters
Dimensions
Thread Parameters
Tip & Drive Parameters
Material & Strength
Temperature & Environment
- Fast delivery
- Enjoy discounts on bulk purchases
- Secure Payment
- Fast Global Shipping
Key Features & Benefits at a Glance
- Maximum load-bearing capacity with Grade 8 classification and 150,000 psi tensile strength for critical structural applications
- Superior corrosion protection through zinc yellow-chromate plating that withstands harsh industrial environments
- Precise thread engagement with Class 2A fit and UNF fine threads ensuring vibration resistance and secure fastening
- Optimized torque transmission via external hex drive design that prevents tool slippage during installation
- Enhanced durability from Rockwell C33 hardness that maintains structural integrity under repeated stress
- Regulatory compliance assurance meeting ASME B18.2.1, SAE J429, RoHS 3, and REACH standards for global industrial use
- Versatile partial threading allowing both clamping and alignment functions in complex assemblies
Professional Applications & Engineering Value
Engineered for heavy-duty industrial applications, these Grade 8 hex head screws solve critical fastening challenges in construction machinery, automotive assemblies, and structural steel frameworks. The 9/16"-18 UNF fine thread configuration provides superior resistance to vibrational loosening compared to coarse threads, while the zinc yellow-chromate plating creates a sacrificial barrier against corrosion in outdoor or chemically aggressive environments. The partially threaded design allows the unthreaded shank to bear shear loads efficiently, making these steel fasteners ideal for pivot points and structural connections where both clamping force and alignment precision are required. With 4" length and external hex drive, they accommodate standard wrenching tools for rapid installation in confined spaces.
Specification Summary & Compliance
Manufactured to precise Class 2A thread fit tolerances with UNF fine thread spacing (18 TPI) on 9/16" diameter. Complies with ASME B18.2.1 dimensional specifications and SAE J429 material standards for Grade 8 fasteners. Meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental compliance requirements. Threading covers minimum 1-3/8" length with right-hand direction on Rockwell C33 hardened steel substrate.
