Sheet Metal Nuts: A Complete Guide to This Unique Fastener


Sheet metal nuts are fasteners that are designed to resist vibrations. Like other locknuts, they don’t loosen or otherwise come undone when exposed to vibrations. Rather, they remain secure, connecting the objects on which they are installed.

What Is a Sheet Metal Nut?

Also known as a speed nut, a sheet metal nut is an anti-vibration fastener that functions as both a locking washer as a well as a nut. They are typically made of low-carbon spring steel. They are called “sheet metal nuts” because they feature two sheet metal prongs on the back. When a bolt is inserted into a sheet metal nut, the sheet metal prongs contract inward to secure the nut in place.

History of Sheet Metal Nuts

The origins of the modern-day sheet metal nut can be traced back to the mid-1930s, during which American inventor Albert Tinnerman developed the first the sheet metal nut. It’s believed that Tinnerman, while working at an oven manufacturing company, invented the steel metal nut to improve the delivery of his company’s products. Prior to its invention, Tinnerman discovered that a substantial number of ovens were becoming damaged during shipping. When ovens were shipped, they would inevitably bounce around during transit, resulting in some of the nuts loosening. The advent of the sheet metal nut solved this problem by resisting the vibrations to which the ovens were exposed during transit.

Although they were originally invented for ovens, sheet metal nuts are now used in dozens if not hundreds of other applications. Their anti-vibration properties makes them an incredibly versatile and useful fastener for a variety of applications. Industrial machines, for example, are often designed with sheet metal nuts rather than traditional nuts because of the constant vibrations they produce.

How Sheet Metal Nuts Work

Sheet metal nuts rely on two prongs of sheet metal to perform their intended operation. Found on the back of the nut, the prongs are designed to expand when an appropriately sized faster is inserted and tightened into the nut. Most sheet metal nuts support machine screws or sheet metal screws. When a supported fastener is tightened inside a sheet metal nut, the prongs on the rear of the nut expand. When this occurs, the prongs push up against the sheet metal nut. This additional pressure prevents the sheet metal nut from loosening when exposed to vibrations. And since sheet metal nuts are made of high-quality spring steel, they don’t suffer from degradation or premature wear and tear.

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