Grade 4 Nylon Lock Nuts

Material: Q235 carbon steel
Strength Grade: Grade 4
Surface Treatment: Electro-galvanized
Thread Specifications: M5, M8, M10, M16, M18, M24 (standard stock, all compliant with DIN 985)

Product Description

A Grade 4 nylon lock nut is a hex nut with an embedded nylon ring; the ‘Grade 4’ denotes its strength grade. Its key advantage lies in the interference fit between the nylon ring and the bolt threads, which provides a self-locking mechanism to prevent loosening. It is suitable for general fastening applications involving low to medium loads and vibrating conditions.

Core structure: Standard hexagonal nut + embedded nylon ring at the top (without pre-formed threads); as the bolt is tightened, the threads cut into the nylon to create an elastic clamping force.
Anti-loosening principle: The compression of the nylon ring generates prevailing torque, which prevents the nut from loosening due to vibration, impact or temperature changes through friction.
Appearance: Hexagonal body, with a black or white nylon ring visible at one end; no specific grade marking (Grade 4 is typically unmarked).

Product Features

Basic anti-loosening	Suitable for general vibration environments; no additional anti-loosening measures (such as spring washers or threadlocker) are required.
Easy installation	Can be fitted using a standard spanner; no special tools required.
Reusability	The nylon ring offers good elasticity and retains its anti-loosening performance after 3–5 cycles of assembly and disassembly (depending on operating conditions).
Cost advantage	Grade 4 is an entry-level anti-loosening nut, offering excellent value for money and suitable for general-purpose bulk applications.
Limitations	Operating temperature ≤ 80°C (nylon softening temperature); not suitable for high-strength or high-temperature applications.

Installation and Use

We recommend using Grade 4.8 bolts to avoid thread damage caused by the bolt having a higher strength than the nut.
The operating ambient temperature must not exceed 80°C; in high-temperature applications, use metal lock nuts or alternative anti-loosening methods.
The nylon ring end should face upwards (away from the connected component), ensuring the bolt passes fully through the nylon ring.
Tighten using a torque wrench to the recommended value to prevent overloading, which could cause the nylon ring to fail.
It is recommended to replace the nut after more than three cycles of assembly and disassembly to ensure anti-loosening performance.

Application Scenarios

General machinery: non-critical components such as small motors, pumps and valves, fans, and conveyor belts.
Electronics and electrical equipment: securing distribution boards, control cabinets, and instruments and gauges.
Furniture and household appliances: domestic appliances with low vibration levels, such as washing machines, air conditioners and fitness equipment.
Automotive parts: interior trim, non-load-bearing chassis components, and securing vehicle lights.
Building and decoration: door and window fittings, railings, and connections in light steel structures.

Manufacturers of fasteners at source

We are a leading manufacturer with many years of experience in the fastener industry, specialising in a wide range of fasteners for industrial, construction and mechanical applications. We offer a comprehensive range of specifications and models, covering numerous commonly used standard parts, providing a one-stop solution for all your procurement needs.

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