S-91257A727 1/2"-13 x 3 3/4" ASME B18.2.1, SAE J429 High-Strength Grade 8 Steel Hex Head Screws

Key Features & Benefits at a Glance

• Exceptional load-bearing capacity with 150,000 psi tensile strength for reliable performance in the most demanding applications
• Superior corrosion resistance provided by zinc yellow-chromate plating, extending service life in harsh environments
• Optimized torque transmission through the external hex drive design, ensuring secure installation and removal
• Enhanced thread engagement with UNC coarse threading that resists vibration loosening and simplifies alignment
• Precision manufacturing to Class 2A thread fit standards, guaranteeing consistent performance and interchangeability
• Robust material integrity with Rockwell C33 hardness, maintaining structural stability under extreme conditions
• Regulatory compliance assurance meeting both industry standards and environmental regulations for global applications

Professional Applications & Engineering Value

These Grade 8 hex head screws deliver critical engineering solutions where failure is not an option. The steel construction with Rockwell C33 hardness provides exceptional resistance to deformation under heavy loads, while the zinc yellow-chromate plating creates a protective barrier against corrosion in industrial environments. The 1/2"-13 UNC coarse thread design ensures rapid installation and superior vibration resistance, making these partially threaded screws ideal for structural connections in heavy machinery, construction equipment, and industrial assemblies. The external hex drive accommodates high torque applications, providing reliable fastening in spaces where socket clearance is limited. These industrial-grade fasteners solve critical challenges in equipment manufacturing, infrastructure projects, and maintenance operations where high-strength screws must withstand extreme mechanical stresses while maintaining long-term reliability.

Specification Summary & Compliance

Manufactured to precise Class 2A thread fit tolerances with UNC coarse threading (1/2"-13), these screws ensure consistent performance across applications. The manufacturing process adheres to ASME B18.2.1 specifications where identified by SAE J429, guaranteeing dimensional accuracy and mechanical properties. Environmental compliance includes RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) standards, confirming these fasteners meet current regulatory requirements for hazardous substance restrictions and chemical safety.