Standard Nylon Insert Lock Nuts

Lock Nuts with a Nylon Insert Stopper

A nylon insert lock nut is hex-shaped, internally threaded with a nylon insert or collar. The nylon material prevents loosening from vibration by increasing friction between the nylon and the screw thread. The insert deforms elastically over the threads of the screw, but threads are not cut into the nylon. This lock nut style is also referred to as a nyloc or nylock nut, polymer insert lock nut, or elastic stop nut.

The nylon insert locks the nut in two ways. First, it forces the bottom face of the screw threads against the nut threads' top face, increasing the friction between them. Second, the nylon applies a compressive force against the screw itself. Nylon lock nuts can maintain this locking ability up to 250 °F or 121 °C.

Nylon lock nuts are not made to be backed-off after being applied. Attempting to do so creates cross threads that stop the nut from backing off the fastener.

Heavy Nylock Nuts

A Nylon Heavy Lock Nut is a thicker version of the traditional nylon lock nut. They are ideal for applications requiring a heavier, stronger, and thicker nut in higher load or some structural applications.

Nylon lock nuts come in a variety of materials including 18-8 and 316 stainless steel, zinc plated steel in various steel grades and classes, aluminum, brass, and chrome plated steel.

Stainless Steel

18-8 or 304 grades of Stainless steel are suitable for many general purpose applications, especially freshwater and non-salt water wet environments. Corrosion-resistant and durable, 18-8 stainless steel is equivalent to the A2 grade of stainless steel.

For much more corrosive environments, such as in saltwater or marine applications, 316 stainless steel is the ideal choice. 316 Stainless steel is equivalent to A4 stainless steel.

Zinc Plated Steel

Zinc is by far the most common and economical type of plating for fasteners. The zinc plating adds a protective "sacrificial" top layer against corrosion while also adding a shiny finish to the fastener. Zinc plating is ideal for indoor use where it won't be constantly exposed to harsh elements.

Most steel grades and classes in this selection have a zinc plating on them. Grade 2, Grade 5, Class 8, and Class 10 steels are all zinc plated. Most Grade 8 steel is also zinc-plated. Specifically, yellow zinc plated to help Grade 8 stand out from the rest of the zinc-plated steel fasteners.

Steel Grades
  • SAE Grade 2 - Low Strength Carbon Steel
  • SAE Grade 5 - Medium Strength Carbon Steel
  • SAE Grade 8 - High Strength, Thru-Hardened Steel
  • Metric Class 8 - Comparable to Grade 5
  • Metric Class 10 - Comparable to Grade 10

Brass

Brass is an alloy made of copper and zinc. The color of brass can vary from dark to light based on the zinc content; more zinc content produces lighter brass. Brass is prized for its appearance and is often used decoratively. However, it is quite soft, so it is not suitable for all applications. Brass conducts electricity and is also a good conductor of heat.

Aluminum

Aluminum is a strong, durable, easily formed, and lightweight metal that is excellent for use in fasteners where strength-to-weight properties are a major requirement. Aluminum has the best strength-to-weight ratio of any metal in common use and corrosion resistance on par with stainless steel.

Chrome Plated Steel

Chrome plating is mostly known for its lustrous finish and is typically used for decorative purposes. The added plating adds an extra layer of corrosion resistance to the fastener. All chrome plated fasteners in this selection are USA made.

FAQs

How does a nylon lock nut work?

Nylon lock nuts have a nylon collar inserted into a recess at the nut's top. This recess and nylon insert are slightly smaller than the outer thread diameter. The insert deforms elastically over the threads of the screw, but threads are not cut into the nylon. This elasticity causes friction between the nylon collar and the screw making the connection resistant to loosening.

Which way do nylon lock nuts go?

Nylon lock nuts go nylon side away from the head of the bolt or screw. The threading should be coming out of the nylon insert side of the nut as the bolt or screw is fastened.

Are Nylock nuts reusable?

Yes, nylon insert lock nuts are reusable. However, we do not recommend frequent repurposing of the same nylon lock nuts in critical connections on a given application.

What is the purpose of a Nylock nut?

Nylock nuts are economical lock nuts for applications involving vibration or motion. The nylon insert of these locking nuts helps the assembly resist loosening under the application's vibration or motion.

How do you use lock nuts?

Most lock nuts are used the same way traditional nuts are; by simply fastening them to the opposite side of a bolt. The locking action activates after the nut is fastened down. The exception to this is castellated nuts and slotted nuts, which needs a hole drilled into the bolt and a cotter pin to finish installation.

Can lock nuts be removed?

They're not designed to be removed easily. If they were, they wouldn't be very good lock nuts! That said, it is possible to remove locknuts. It may require some patience and, in some cases, power tools to remove them. The exact method will vary based on application and lock nut.

Do you need a lock washer with a lock nut?

No, you don't need a locking washer to use a locking nut or vice versa. Most applications will call for using one or the other, not both. That's not to say you can't use both a lock nut and lock washer as part of the same assembly. It's just not common to do so; one will suffice for most jobs.