Value Collection 31-NU-62C Heavy Hex Lock Nut 5/8-11

Product Description

The VALUE COLLECTION 31-NU-62C is a heavy hex lock nut with a nylon insert, designed to maintain clamp load and resist loosening under vibration and dynamic loads. Built from 18-8 stainless steel with a bright, uncoated finish, it offers solid corrosion resistance for general-purpose and marine-adjacent applications. The 5/8-11 UNC thread size and right-hand thread direction make it a standard fit for a wide range of structural and mechanical assemblies. At 55/64 inches high with a 1-1/16 inch width across flats, this heavy hex profile provides greater bearing surface than standard hex, distributing load more evenly across the joint. Installed by millwrights, pipefitters, and maintenance technicians wherever a reliable prevailing-torque locking solution is needed.

This lock nut is suited for industrial, commercial, and mechanical installations where vibration resistance is a priority. The nylon insert creates a prevailing torque that resists self-loosening without requiring a secondary locking element such as a lock washer or thread adhesive. Its 18-8 stainless steel construction handles exposure to moisture and mild corrosives, making it appropriate for HVAC structural connections, plumbing equipment mounts, and general plant maintenance assemblies requiring a 5/8-11 UNC fastener.

Key Features

• Nylon insert locking style provides reliable prevailing torque without additional hardware
• 18-8 stainless steel material offers corrosion resistance in wet or outdoor environments
• Heavy hex profile with 1-1/16 inch width across flats increases bearing surface over standard hex
• 5/8-11 UNC right-hand thread for compatibility with standard inch-series fasteners
• Bright, uncoated finish suitable where bare stainless is acceptable or required
• Width across points of 1.1750 inches accommodates standard heavy hex tooling

Compatibility

Designed as an OEM-style replacement or standard procurement item for assemblies requiring a 5/8-11 UNC heavy hex nylon insert lock nut in 18-8 stainless steel.

Installation Notes

Install with a standard heavy hex wrench or socket sized for the 1-1/16 inch width across flats. Power down or de-energize any associated equipment before performing fastener work on mechanical systems. Nylon insert lock nuts are intended for single-use applications — the nylon element loses clamping integrity after removal and the nut should not be reused in critical joints. Follow applicable mechanical and structural codes for torque sequence when used in multi-bolt flange or structural connections.