Jam Nuts vs Hex Nuts: What’s the Difference?


Jam nuts by Monroe

It’s a common misconception that jam nuts and hex nuts are the same. They feature a similar shape, and they are available in similar materials. Because of their similarities, many people assume that they are the same. Jam nuts and hex nuts, differ, however, in a few ways.

What Are Hex Nuts?

Hex nuts are hexagonal fasteners with interior threading that are used in conjunction with a bolt. With their hexagonal shape, they have six sides of equal length. You can install hex nuts by twisting them onto a bolt. Some hex nuts can be hand-tightened, whereas others may require the use of a wrench. Regardless, their interior threading allows them to be twisted onto — and twisted off of — bolts.

What Are Jam Nuts?

Jam nuts are hexagonal fasteners with interior threading that are designed to press or jam against another nut. Like hex nuts, they feature a hexagonal shape. Jam nuts have six sides of equal length, and they have the same interior threading as their hex nut counterparts.

Differences Between Hex Nuts and Jam Nuts

Hex nuts and jam nuts are both hexagonal fasteners with interior threading. How do they differ exactly? The term “hex nut” refers to any nut with a hexagonal shape. Jam nuts have a hexagonal shape, so they are considered a type of hex nut. But jam nuts are designed specifically to press or jam against another, standard nut.

Nuts can loosen. When exposed to vibrations, for instance, a nut may gradually work its way off the bolt. And without the nut holding the bolt in place, the bolt may come out of the workpiece or machine. Jam nuts prevent this from happening by pressing or jamming against the existing nut.

Most jam nuts are thinner than standard nuts. You can twist a jam nut onto a bolt, after which you can twist a standard nut onto the same bolt. As the two nuts press against each other, they’ll provide a higher level of security. Vibrations or mechanical stress won’t loosen them. The jam nut will hold the other nut in place so that neither of them loosens — even if they are exposed to regular vibrations.

In Conclusion

While similar, hex nuts and jam nuts aren’t the same. Hex nuts consist of all nuts with a hexagonal shape. Jam nuts are thinner hexagonal nuts that are designed to press or jam against another nut.