Nyloc Nut

A Nyloc nut, also called a nylon-insert lock nut, polymer-insert lock nut, or elastic stop nut, is a standard metal hex nut with a nylon collar inserted at the top. This nylon insert has an inner diameter slightly smaller than the bolt’s major diameter, which allows it to deform elastically over the threads when tightened, creating friction that locks the nut in place 

How They Work

When a Nyloc nut is threaded onto a bolt, the threads cut into or press against the nylon insert, depending on the design, generating friction that resists loosening from vibration or movement . This friction also helps form a tight seal, reducing the ingress of liquids such as oil, water, or gasoline . Unlike lock washers, Nyloc nuts maintain their locking ability even under continuous vibration 

Advantages

• Vibration resistance: Ideal for applications subject to movement or vibration.
• Sealing capability: Helps prevent liquid seepage along the bolt threads.
• Versatility: Available in various grades and materials, including stainless steel and zinc-plated steel, suitable for DIY, automotive, and industrial use 
• Reusability: Can be reused multiple times, though efficiency decreases with each use 

Limitations

• Temperature sensitivity: Nylon inserts degrade at high temperatures, typically above 121–177°C depending on the manufacturer 
• Heavy-load applications: For extremely high loads, mechanical locking methods like castellated nuts with cotter pins may be more appropriate

This is for ONE singular Nyloc Nut