S-91257A487 7/16"-20 x 8" ASME B18.2.1, SAE J429 High-Strength Grade 8 Steel Hex Head Screws

Key Features & Benefits at a Glance

• Maximum Load-Bearing Capacity with 150,000 PSI tensile strength and Grade 8 classification, ensuring reliable performance under extreme stress.
• Superior Corrosion Resistance from zinc yellow-chromate plating, extending service life in harsh industrial environments.
• Precise Thread Engagement with Class 2A UNF fine threads, providing secure fastening and vibration resistance.
• High Durability backed by Rockwell C33 hardness, maintaining structural integrity under repeated use.
• Easy Installation & Removal using standard external hex drive and 5/8" head width for straightforward tool compatibility.
• Optimized Load Distribution through partial threading design, concentrating strength where needed most.
• Industry Compliance meeting ASME B18.2.1 and SAE J429 standards for guaranteed quality and interchangeability.

Professional Applications & Engineering Value

Engineered for heavy-duty industrial applications, these Grade 8 hex head screws address critical challenges in machinery assembly, structural steel connections, and high-vibration equipment. The 7/16"-20 UNF thread with fine spacing ensures superior clamping force and resistance to loosening under dynamic loads. Combined with zinc yellow-chromate plating, the fastener delivers exceptional corrosion protection in demanding environments like manufacturing plants, construction sites, and automotive systems. The partially threaded design allows unthreaded shank sections to bear shear loads directly, while the external hex drive enables high-torque installation with common tools. This combination of high tensile strength and corrosion resistance makes it ideal for applications where failure is not an option.

Specification Summary & Compliance

This 8-inch hex head screw features precise Class 2A thread fit with 7/16"-20 UNF fine threading and 1 3/8" minimum thread length. Manufactured to ASME B18.2.1 and SAE J429 specifications, it ensures dimensional accuracy and mechanical properties for industrial use. The inch system measurement and steel material construction provide consistent performance, while the plating process meets industry standards for corrosion protection.