Photo by Marcel Strauß

Originally Posted On: Know Your Nuts: All Metal Lock Nuts (mudgefasteners.com)

In our next edition of Know Your Nuts, we’re going to review the different types of all metal lock nuts. Designed to develop a “prevailing torque” between the bolt threads and nuts threads, all metal lock nuts increase the resistance to rotation in an assembly. Unlike nylon insert lock nuts, these nuts are effective in higher temperature environments (withstanding temperatures up to 1,400 °F ), since they’re completely made of metal. Below is a summary of the most common all metal lock nuts available.

Flange Nuts

Flange nuts feature a wide flange at one end that acts like an integrated washer, distributing the torquing pressure placed the nut across the surface of the material it’s being secured to. Often including serrations on the underside of the flange, these nuts are regularly used in assembly lines where the speed of using a single fastener, as opposed to separate nuts and washers, can help increase productivity and overall output.

Keps Nuts

Keps nuts are similar looking to standard hex nuts, but also include an attached, free-spinning washer. The washer is sometimes called a k-lock or star washer. A trademark of ITW Shakeproof, the name Keps is a reference to the “kep” in ShaKEProof, with an “s” typically added because more than one is purchased at a time.

Stover Lock Nuts

Stover lock nuts are single-piece, prevailing torque hex nuts that feature a conical top, flat bottom bearing surface, and chamfered corners. In Stover lock nuts, the locking action is created by distortion of their top threads during torquing, and can withstand severe shock loads and vibration.

Two-Way Reversible Lock Nuts

In a two-way reversible lock nut, a standard hex nut is compressed with two or three indentations on the flat sides of the nut. These compressions can be circular or rectangular, but must be equal distances from each other. In order to create a controlled locking mechanism, the compressions slightly distort the center threads that lock when engaged with the mating bolt or screw. Designed for use with machine screws and low-carbon bolts, the two-way reversible lock nut allows for automatic assembly.

If you have further questions about all metal lock nuts, please don’t hesitate to contact us for more information.