S-91257A656 3/8"-16 x 12" 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 yellow-chromate plating extends service life in harsh industrial environments
- Precision Class 2A thread fit guarantees consistent engagement and secure fastening in assembly operations
- High hardness rating (Rockwell C33) maintains structural integrity under extreme mechanical stress and vibration
- Optimized partial threading allows for focused thread engagement where maximum clamping force is required
- Standard-compliant manufacturing ensures interchangeability and compatibility with existing industrial systems
- External hex drive design enables high-torque installation with common industrial tools for efficient assembly
Professional Applications & Engineering Value
Engineered for critical heavy-duty applications, these Grade 8 hex head screws deliver exceptional performance in construction, machinery assembly, and structural frameworks. The 3/8"-16 UNC coarse thread configuration provides superior resistance to vibration loosening while enabling rapid installation in thick materials. The zinc yellow-chromate plating creates a protective barrier against corrosion, significantly extending service life in outdoor or chemically aggressive environments. With partial threading concentrating the clamping force precisely where needed, these steel fasteners solve common engineering challenges of joint integrity and long-term reliability in high-stress connections. The combination of 150,000 psi tensile strength and Rockwell C33 hardness ensures these bolts maintain their mechanical properties under continuous load conditions.
Specification Summary & Compliance
These hex head screws feature precision Class 2A thread fit with 3/8"-16 UNC coarse thread spacing and partial threading over a minimum length of 1-1/4". Manufactured from high-strength steel with zinc yellow-chromate plating finish, they comply with ASME B18.2.1 and SAE J429 Grade 8 specifications, ensuring dimensional accuracy and mechanical performance standards are met for industrial applications.
