Value Collection 39667 Hex Lock Nut 5/8-18 Grade 8

Product Description

The VALUE COLLECTION 39667 is a 5/8-18 UNF hex lock nut with a nylon insert locking mechanism, manufactured from Grade 8 steel with a zinc yellow dichromate finish. The nylon insert deforms around the mating thread under torque, creating a prevailing-torque lock that resists vibration-induced loosening without requiring a secondary locking element. At 3/4 inches tall and 15/16 inches across the flats, this nut seats flush in standard hex wrench and socket tooling. The zinc yellow dichromate coating provides moderate corrosion resistance. Installers working in HVAC, plumbing, electrical, or general mechanical assembly applications will find this nut suitable for high-strength fastening tasks.

This hex lock nut is suited for structural and mechanical assemblies where joint integrity under vibration or thermal cycling is a requirement. The 5/8-18 UNF fine thread pitch increases thread engagement per inch compared to coarse thread, making it a common choice in precision mechanical, automotive, and equipment manufacturing applications. Right-hand thread direction conforms to standard practice. Sold individually with a minimum order quantity of 10 units.

Key Features

• Nylon insert locking style resists loosening from vibration without secondary hardware
• Grade 8 steel construction for high-strength fastening applications
• 5/8-18 UNF fine thread for increased thread engagement per inch
• Zinc yellow dichromate finish provides moderate corrosion resistance
• Right-hand thread direction per standard UNF fastener practice
• 3/4 inch height and 15/16 inch across-flats dimension for standard socket and wrench tooling

Compatibility

Designed as a standard UNF replacement or service hex lock nut for 5/8-18 fine-thread applications in mechanical, structural, and equipment assembly contexts.

Installation Notes

Installation is performed with a standard 15/16 inch hex socket or open-end wrench. Ensure the mating bolt or stud is clean and free of debris before threading the nut. Nylon insert lock nuts are typically rated for single use — once the insert has been fully seated and removed, inspect the nylon element before reuse. Follow applicable torque guidelines for Grade 8 fasteners as specified by the equipment manufacturer or relevant mechanical standards.