S-91257A967 1"-8 x 5 1/2" 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 and Grade 8 classification for reliable performance in high-stress environments.
• Superior corrosion resistance due to zinc yellow-chromate plating, extending service life in harsh or outdoor industrial settings.
• Optimized thread engagement with UNC coarse threading and Class 2A fit, ensuring quick assembly and secure fastening in heavy machinery.
• Robust material integrity from steel construction and Rockwell C33 hardness, providing excellent durability and resistance to wear.
• Enhanced torque application with an external hex drive and 1 1/2" head width, allowing for easy installation with standard tools.
• Versatile partial threading design (minimum 2 1/4" thread length) for precise clamping force control in structural applications.
• Compliance with industry standards including ASME B18.2.1 and SAE J429, guaranteeing consistent quality and interchangeability.

Professional Applications & Engineering Value

This Grade 8 hex head screw is engineered to address critical challenges in heavy-duty industrial applications, such as construction equipment, agricultural machinery, and transportation infrastructure. The steel material combined with Rockwell C33 hardness ensures it withstands extreme vibrations and dynamic loads without fracturing. The zinc yellow-chromate plating offers a protective barrier against moisture and chemicals, reducing maintenance needs in corrosive environments. With 1"-8 UNC coarse threading and partial threading, it provides superior grip in soft materials and allows for precise joint tensioning, minimizing the risk of loosening. Ideal for high-strength bolting in assemblies requiring reliable, long-term fastening solutions, this screw delivers consistent performance under demanding conditions.

Specification Summary & Compliance

This fastener meets precise dimensional tolerances with a Class 2A thread fit and adheres to UNC thread standards for consistent compatibility. Manufacturing follows ASME B18.2.1 and SAE J429 specifications, ensuring reliability in mechanical properties. It is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, confirming the absence of hazardous substances for safe use in various industries.