A speed nut, also known as a sheet metal 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.
History
The speed nut was invented by Albert H. Tinnerman, son of George Tinnerman (who founded Tinnerman Stove Company), in 1936. This is why speed nuts are sometimes known as Tinnerman nuts. Albert invented the nut to resolve issues with stove shipping. The invention was so successful it led the company away from building stoves to building fasteners. Tinnerman Products evolved from the speed nut development with manufacturing plants in Cleveland, Ohio. A modern manufacturing plant was constructed on Brookpark Road in the mid-1950s. Tinnerman Products was later acquired by Eaton Yale & Towne (Eaton Corporation).