MIDWEST FASTENER CORP 51868 Nylon Insert Lock Nut 3/8"-24 Steel Grade 8 Yellow hardware

3/8"-24 Grade 8 lock nut

This nylon-insert lock nut is a Grade 8 steel fastener designed to resist loosening under vibration and torque. The yellow finish provides visible corrosion protection for automotive and industrial assemblies. It suits mechanics and technicians who need a reliable prevailing-torque nut for critical joints. The 3/8"-24 thread matches fine-pitch requirements in many chassis and drivetrain applications.

Fine-pitch thread and prevailing torque

The 3/8"-24 thread delivers tighter thread engagement than coarse alternatives, helping maintain clamp load in high-vibration zones. The nylon insert grips the bolt threads without damaging them, giving reusable locking performance until the insert wears. It handles repeated assembly and disassembly cycles where a free-spinning nut would back off. Once the nylon degrades from heat or repeated use, the locking function diminishes and the nut must be replaced.

Replaces standard hex nuts in vibration-prone joints

Swapping a plain hex nut for this lock nut adds vibration resistance without changing bolt length or tool size. The upgrade is worth it on suspension links, bracket mounts and engine accessories where loosening causes noise or safety issues. It does not suit joints that see temperatures above the nylon’s limit or applications requiring a metal-only locking element. Buyers needing a flange face, a different thread pitch or a higher temperature rating must select another part.