S-91257A731 1/2"-13 x 4 3/4" ASME B18.2.1, SAE J429 High-Strength Grade 8 Steel Hex Head Screws

Key Features & Benefits at a Glance

• Maximum load-bearing capability 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
• Optimized thread engagement with UNC coarse threading and Class 2A fit ensuring reliable installation and vibration resistance
• Enhanced driving efficiency with external hex drive and 3/4" head width for secure tool engagement and high torque application
• Precision-engineered dimensions maintaining 4 3/4" length with 1 1/4" minimum thread length for consistent performance across assemblies
• Exceptional material durability featuring Rockwell C33 hardness steel that resists deformation under extreme pressure
• Industry-standard compliance meeting ASME B18.2.1 and SAE J429 specifications for guaranteed interoperability

Professional Applications & Engineering Value

Engineered for heavy-duty industrial applications, these Grade 8 hex head screws deliver exceptional performance in construction, machinery assembly, and structural frameworks where failure is not an option. The partially threaded design provides optimal clamping force distribution while the coarse UNC threading ensures rapid installation in tough materials. The Zinc Yellow-Chromate plating creates a protective barrier against corrosion in outdoor or high-moisture environments, significantly extending service life. With 150,000 psi tensile strength and Rockwell C33 hardness, these fasteners maintain integrity under extreme vibrational loads and shock impacts, making them ideal for heavy equipment manufacturing and critical infrastructure projects where reliability is paramount.

Specification Summary & Compliance

Manufactured to exacting Class 2A thread fit tolerances with 1/2"-13 UNC coarse threading and right-hand thread direction. Complies with ASME B18.2.1 dimensional standards and SAE J429 material specifications for Grade 8 fasteners. Features 4 3/4" overall length with 1 1/4" minimum thread length and external hex drive configuration. The steel construction with Zinc Yellow-Chromate finish meets industrial corrosion resistance requirements while maintaining 150,000 psi tensile strength and Rockwell C33 hardness properties.