S-99891A210 1 1/4"-12 Hex Nuts

Key Features & Benefits at a Glance

• Maximum load-bearing capability with Grade 8 strength classification, ensuring reliable performance in high-stress industrial environments
• Superior corrosion resistance from zinc yellow-chromate plating, extending service life in harsh or outdoor applications
• Precise thread engagement with Class 2B fit and fine UNF threads, providing vibration resistance and secure fastening
• Left-hand threading compatibility for specialized machinery and safety-critical applications requiring reverse rotation
• Standard external hex design for universal tool compatibility and straightforward installation with common wrenches
• Heavy-duty dimensional profile (1 7/8" width, 1 1/16" height) offering substantial bearing surface for distributed load pressure
• Interchangeable compliance with inch measurement system standards, ensuring replacement part compatibility

Professional Applications & Engineering Value

This Grade 8 left hand thread hex nut addresses critical engineering challenges in heavy machinery, automotive, and construction applications where reverse-direction forces are present. The zinc yellow-chromate plated steel construction provides dual protection against corrosion and galvanic reactions, significantly reducing maintenance frequency in exposed environments. The fine UNF threads with Class 2B fit maintain clamping force under sustained vibration, preventing costly downtime from loosening in equipment like rotating assemblies, power transmission systems, and hydraulic components. The left-hand threading serves as a safety feature in applications where standard right-hand rotation could cause unintended disassembly, making it essential for specific shaft orientations, mixer blades, and torque-sensitive installations.

Specification Summary & Compliance

Manufactured to exacting standards with Class 2B thread fit tolerances and UNF fine thread specifications (1 1/4"-12). This external hex nut complies with ASME/ANSI B18.2.2 dimensional requirements for standard hex nuts in the inch measurement system. The Grade 8 classification confirms consistent mechanical properties meeting or exceeding 150 ksi minimum tensile strength. Material composition and zinc yellow-chromate plating process adhere to RoHS and REACH environmental compliance standards for industrial fastener applications.