ThePipingMart Blog Fasteners Lock Nut vs Jam Nut – What’s the Difference

Lock Nut vs Jam Nut – What’s the Difference

Lock Nut vs Jam Nut

If you are looking to secure a fastener in place, chances are you have heard the terms “lock nut” and “jam nut” thrown around. But what do they mean? Understanding the differences between these two types of nuts can help ensure that your fastening job is done right. Let’s take a look at how lock nuts and jam nuts work, as well as when and why you should use each one.

What is Lock Nut?

A lock nut—also known as a locking nut or nylon insert lock nut—is designed to keep screws from loosening due to vibration or other forces. It does this by using a nylon insert that expands when it is tightened into place, creating friction between the threads of the bolt and the nut that holds it in place. This makes lock nuts ideal for applications where vibration or movement could cause a bolt to come loose over time.

What is Jam Nut?

On the other hand, a jam nut is designed to act as a locking mechanism for another nut to keep it from moving or loosening up over time. It works like a regular nut but is thinner than usual, so it can fit snugly against another larger nut while still providing ample threading space for bolts. The idea behind jam nuts is that they provide additional security by preventing an attached nut from being moved without first having to loosen two separate sets of threads—the jam nut itself and then whatever else is attached to it.

Difference Between Lock Nut and Jam Nut

  • A lock nut is a type of nut that is used to secure a bolt or screw in place.
  • A jam nut is a type of nut that is used to secure two bolts or screws together.
  • Lock nuts are made from steel, while jam nuts are made from brass.
  • Lock nuts have a higher level of torque than jam nuts.
  • Jam nuts are easier to remove than lock nuts.
  • Lock nuts are more expensive than jam nuts.


Whether you are looking for added security against vibration or need something extra safe, understanding which type of fastener will be best suited for your project can help ensure success. Locknuts offer superior anti-vibration protection, while jam nuts provide extra protection for nuts already in place against accidental loosening over time. They are knowing which one to use when can help save you time and money down the line!

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