S-91211A166 3/8"-16 x 2 1/2" ASME B18.2.1, SAE J429 High-Strength Grade 8 Steel Thread-Locking Hex Head Screws

Key Features & Benefits at a Glance

• Exceptional vibration resistance with a permanent Nylon Patch thread locker that maintains integrity from -55° to 250°F, preventing loosening in dynamic environments.
• Superior tensile strength of 150,000 psi and Rockwell C33 hardness, ensuring reliable performance under high-stress conditions.
• Corrosion-resistant zinc yellow-chromate plating on steel for enhanced durability and longevity in harsh industrial settings.
• Secure and easy installation with an external hex drive and coarse UNC threading, allowing for quick assembly with standard tools.
• Optimized load distribution due to the partially threaded design, reducing stress concentration and improving joint stability.
• Compliance with industry standards including ASME B18.2.1 and SAE J429, guaranteeing consistent quality and interchangeability.
• Versatile inch system sizing with a 2 1/2" length and 3/8"-16 thread, ideal for a wide range of heavy-duty applications.

Professional Applications & Engineering Value

This Grade 8 hex head screw is engineered to address critical challenges in industrial fastening, such as vibration-induced failure and corrosion. The zinc yellow-chromate plated steel construction provides excellent resistance to environmental factors, extending service life in demanding settings like machinery, construction, and automotive assemblies. The Nylon Patch thread locker ensures a permanent lock without the need for additional adhesives, simplifying maintenance while offering reliable performance across a broad temperature range. With its coarse UNC threads and partial threading, it facilitates faster installation and better clamp load control, reducing the risk of strip-out in soft materials. These features make it an ideal choice for applications requiring high-strength, durability, and compliance with ASME and SAE specifications, ultimately minimizing downtime and enhancing operational safety.

Specification Summary & Compliance

This fastener adheres to precise dimensional standards with a Class 2A thread fit and UNC coarse spacing, ensuring consistent performance and easy replacement. It meets ASME B18.2.1 and SAE J429 specifications, confirming its reliability for heavy-duty use. The manufacturing process aligns with industry norms for Grade 8 strength, supported by a tensile strength of 150,000 psi and Rockwell C33 hardness. While specific RoHS or REACH declarations are not provided, the materials and plating are typical for industrial compliance, offering a robust solution for professional applications.