S-99891A120 3/8"-16 Hex Nuts

Key Features & Benefits at a Glance

• Exceptional strength and reliability with Grade 8 classification, ensuring high load-bearing capacity for demanding industrial applications.
• Superior corrosion resistance provided by zinc yellow-chromate plating, extending service life in harsh or outdoor environments.
• Precise left-hand threading for specialized assemblies requiring reverse rotation, preventing unintended loosening in specific machinery.
• Coarse UNC thread design enables quick installation and removal, reducing assembly time and labor costs.
• Consistent Class 2B thread fit guarantees smooth engagement with mating bolts, minimizing the risk of cross-threading and improving joint integrity.
• Durable external hex drive allows for easy wrench access and secure tightening, even in confined spaces.
• Wide compatibility with inch-standard components, making it ideal for North American industrial equipment and maintenance.

Professional Applications & Engineering Value

This Grade 8 left hand thread hex nut is engineered to address critical challenges in heavy-duty and high-vibration environments. Made from zinc yellow-chromate plated steel, it offers robust protection against rust and chemical exposure, which is essential for outdoor machinery, automotive systems, and construction equipment. The 3/8"-16 UNC coarse thread and left-hand direction are specifically designed for applications where standard right-hand threads may loosen under counter-clockwise motion, such as in rotating shafts or specific motor assemblies. By ensuring a secure Class 2B fit, this nut maintains consistent clamping force, reducing maintenance frequency and enhancing operational safety. Its external hex drive simplifies installation with common tools, supporting efficient assembly lines and reducing downtime in industrial settings.

Specification Summary & Compliance

This hex nut adheres to inch measurement standards with a thread size of 3/8"-16 UNC and Class 2B thread fit for precise tolerance. It meets the Grade 8 strength requirements under relevant ASME or SAE specifications, ensuring high tensile and proof load performance. The zinc yellow-chromate plating complies with RoHS and REACH environmental directives, providing a safe and durable finish. Manufactured to consistent industrial fastener standards, this nut is suitable for use in regulated and high-stress applications.