S-91268A313 3/8"-16 x 4" 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 demanding applications
- Superior wear resistance due to Rockwell C33 hardness, ensuring extended service life under high-stress conditions
- Optimized thread engagement with UNC coarse threads and Class 2A fit for faster assembly and reduced cross-threading risks
- Enhanced torque transmission through the external hex drive design, allowing for secure tightening with standard tools
- Controlled thread distribution with partial threading to concentrate strength where needed most in joint assemblies
- Full regulatory compliance meeting ASME B18.2.1 and SAE J429 specifications for guaranteed interchangeability and performance
- Environmentally responsible manufacturing with RoHS 3 and REACH compliance for safe use in regulated industries
Professional Applications & Engineering Value
Engineered for heavy-duty industrial applications, these Grade 8 hex head screws deliver critical reliability where failure is not an option. The 3/8"-16 UNC coarse thread configuration provides superior resistance to vibration loosening while enabling rapid installation in structural steel, machinery frames, and equipment bases. The 150,000 PSI tensile strength combined with Rockwell C33 hardness ensures these fasteners maintain clamp force under extreme dynamic loads and shock conditions. The partially threaded design concentrates the thread engagement in the critical load zone while the unthreaded shank provides enhanced shear strength. These steel fasteners with external hex drive are specifically engineered for applications requiring predictable, repeatable performance in construction, manufacturing, and heavy equipment maintenance.
Specification Summary & Compliance
Manufactured to precise dimensional standards with Class 2A thread fit tolerance for consistent performance. Complies with ASME B18.2.1 and SAE J429 specifications for Grade 8 fasteners. Meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental compliance requirements. Features 3/8"-16 UNC coarse threads with right-hand thread direction and 1" minimum thread length on a 4" overall length configuration.
