What Are Jam Nuts and How Do They Work?

Jam nuts by Monroe

Nuts are commonly used with threaded fasteners. You can just run a threaded fastener through two parts. If the back of the threaded fastener is exposed, the parts may break away from each other. A nut will prevent this from happening. Twisting a nut onto the end of the threaded fastener will hold the two parts together.

Some nuts, however, are shorter than others. Jam nuts are characterized by a shorter height than that of standard nuts. What are jam nuts exactly, and how do they work?

What Are Jam Nuts?

Jam nuts are short, threaded nuts. Most of them are hexagonal — just like other nuts. The difference, of course, lies in their height. Jam nuts are about half as tall as ordinary nuts. With their shorter height, they essentially work like locknuts.

How Jam Nuts Work

They are known as “jam nuts” because they are designed to jam against another nut. Nuts, of course, may loosen or even fall off the threaded fasteners on which they are used. Vibrations can cause nuts to loosen over time. Mechanical stress can also cause them to loosen. Fortunately, there are locknuts available to prevent this from happening.

Locknuts are threaded nuts that are designed to resist loosening. With that said, they require the use of another nut to achieve this locking functionality. When using a jam nut as a locknut, you’ll need to press it against another nut. Assuming the threaded fastener already has a standard nut on it, you can twist a jam nut on. As the jam nut presses against the standard nut, it will stay in place.

While jam nuts are typically used as locknuts — which requires the use of another, standard nut — they can also be used by themselves. Jam nuts are short. Their short height allows them to fit into small spaces.

If you’re trying to secure parts with a short threaded fastener, you may want to use a jam nut. Jam nuts are shorter than other types of nuts Even if a standard nut won’t fit, you may be able to twist a jam nut onto the threaded fastener. Their short height makes them ideal for short threaded fasteners and small spaces.

In Conclusion

Jam nuts are simply short nuts. They are available in different materials and different threading, but they are all shorter than standard nuts. Most jam nuts are used as locknuts. They are twisted onto threaded fasteners, and as they press against an existing nut, they’ll stay in place.

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