Value Collection 39643 Hex Lock Nut 7/8-14 Grade 8

Product Description

The VALUE COLLECTION 39643 is a 7/8-14 UNF hex lock nut with a nylon insert locking mechanism, manufactured from Grade 8 steel with an uncoated finish. The nylon insert creates prevailing torque that resists loosening caused by vibration and dynamic loads, making it a reliable fastener for demanding mechanical assemblies. At 63/64 inches in height with a 1-1/4-inch width across the flats, it fits standard hex tooling and is sized for heavy-duty fastening applications. Plumbers, HVAC technicians, and mechanical contractors use Grade 8 nylon insert lock nuts where high-strength, vibration-resistant connections are required.

This hex lock nut is suited for use in high-vibration mechanical and structural assemblies where a standard hex nut would not maintain clamp load. The 7/8-14 UNF thread designation indicates a fine-thread pattern, which provides greater thread engagement per inch compared to coarse-thread fasteners. Fine-thread nuts are commonly selected in applications requiring precise torque control or where joint material thickness is limited. The uncoated finish is appropriate for dry or controlled-environment installations where corrosion resistance is not a primary requirement.

Key Features

• Nylon insert locking style provides prevailing torque resistance against vibration-induced loosening
• Grade 8 steel construction delivers high tensile and proof-load strength
• 7/8-14 UNF fine-thread pattern for precise thread engagement
• Right-hand thread direction, standard for general mechanical assembly
• Uncoated finish for use in dry or interior applications
• 1-1/4 inches across flats — fits standard 1-1/4 inch hex tooling

Compatibility

Designed as a standard UNF-thread hex lock nut for use with 7/8-14 Grade 8 threaded fasteners in mechanical, HVAC, plumbing, and structural assemblies requiring a nylon insert prevailing-torque nut.

Installation Notes

Installation should be performed by a qualified mechanic or trade professional using a properly sized 1-1/4 inch wrench or socket. De-energize and relieve all pressure or load from the assembly before disassembly or nut replacement. Nylon insert lock nuts are generally rated for single use — inspect the nylon collar before reuse, as the prevailing torque resistance diminishes after the first installation cycle. Follow applicable torque requirements for Grade 8 fasteners as specified by the equipment manufacturer or relevant industry standards.