Speed nut

A speed nut, aka sheet metal nut or Tinnerman nut, is a type of locknut with two sheet metal prongs that act as one thread. They are made from spring steel.

The fastener serves the functions of both a lock washer and a nut. As the fastener is tightened in the nut the prongs are drawn inward until they exert pressure on the root of the thread on the fastener. When the fastener is tightened, the base of the nut, which is arched, elastically deforms and applies a force to the fastener, which locks it from loosening under vibrations.

There are many different types of speed nuts, mostly dependent on the shape of the nut, how it attaches to the workpiece, and what type of screw can be used. Most types are designed for either machine screws or sheet metal screws. Some nuts do not attach to the workpiece. These are usually shaped as either a rectangle, a flange nut, or a hex nut; the rectangular speed nut is also known as a flat-style speed nut. Speed nuts that attach to the workpiece usually are some form of a J-nut or U-nut.