Flange Nuts: Types and Uses

Posted by Fasteners Plus International on January 4th, 2018

A flange nut is a metal fastening device that is commonly used to lock two surfaces together securely. It is basically a nut that has an integrated bottom lip or flange that allows it to be used with or without a separate washer arrangement. The integrated flange serves to help distribute the pressure of the nut evenly around the area that is being secured to allow for a tighter and more stable fit. This reduces the chances of it being loosened due to an uneven surface contact on the face of the section that is being secured together.

There are two variants commonly available for flanged nuts. These are the serrated face flange nut, and the Keps nut, or K-Nut for short.

A serrated face nut is essentially a flange nut with a serrated flange face facing the contact surface. The serrations or ridges along the flange face bite into the contact surface to provide a locking action that prevents the nut from easily coming undone by vibrations or uneven machining of the contact surface. It is not advisable to use a washer with a serrated face nut as this nullifies the locking action and can cause the nut to loosen over time. These types of nuts can be used with spacers or extra washers, provided a locking washer is included to secure the nut.

On the other hand, Keps nuts, or K-nuts (also called washer nuts), refer to those that come with an integrated free spinning washer. This make assembly convenient and prevents loose washers from falling off like that on a conventional washer arrangement. They are also known as jet nuts as they are a special type of hex nut commonly used in the aerospace and automotive racing industries. K-nuts are generally smaller and shallower than a standard hex nut. Expect it to have a free spinning flange on one end, which acts as a lock when tightened, thanks to an elliptical offset on the unflanged side of the nut, which causes it to push down on the flange and compress a set of teeth set around the edge of the flange. The teeth then bite into the contact surface under compression, thereby locking the nut in place.

About the Author:
Al Anderson, General Manager, Fasteners Plus International

Fasteners Plus International is a full line fastener distributor, who provides a wide range of standard, metric and custom fastening solutions to users around Chicago, US. They are also an exclusive distributor in all of North America for Hard Lock self-locking nuts, and aims to offer most secure fastening solution for extreme vibration environments