S-91286A199 5/16"-24 x 3" 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 the most demanding heavy-duty applications
- Superior corrosion resistance provided by zinc-flake coating extends service life in harsh industrial environments
- Precision Class 2A thread fit guarantees smooth installation and secure fastening with consistent engagement
- Grade 8 strength classification with Rockwell C33 hardness delivers maximum durability and fatigue resistance
- UNF fine threading provides superior vibration resistance compared to coarse thread alternatives
- Partially threaded design allows for optimal clamping force distribution across joint surfaces
- External hex drive enables high-torque installation with standard tools for efficient assembly
Professional Applications & Engineering Value
These Grade 8 hex head screws are engineered to solve critical fastening challenges in industrial applications where failure is not an option. The combination of 150,000 psi tensile strength and Rockwell C33 hardness ensures these steel fasteners maintain integrity under extreme loads and vibration. The zinc-flake coating provides superior corrosion protection, making them ideal for outdoor equipment, machinery, and structural applications exposed to environmental elements. The 5/16"-24 UNF fine thread configuration offers enhanced resistance to loosening in high-vibration environments, while the partially threaded design concentrates clamping force precisely where needed. These industrial hex screws deliver reliable performance in construction equipment, automotive assemblies, and heavy machinery where safety and durability are paramount.
Specification Summary & Compliance
Manufactured to ASME B18.2.1 and SAE J429 Grade 8 specifications with Class 2A thread fit tolerance for precision engagement. Features 5/16"-24 UNF fine threads with right-hand orientation and 3" length with minimum 7/8" thread length. Full compliance with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, ensuring safe use across global industrial markets.
