A swage nut or self-clinching nut is a type of nut or

threaded insert A threaded insert, also known as a threaded bushing, is a fastener element that is inserted into an object to add a threaded hole. They may be used to repair a stripped threaded hole, provide a durable threaded hole in a soft material, place a thr ...

that is used on

sheet metal Sheet metal is metal formed into thin, flat pieces, usually by an industrial process. Sheet metal is one of the fundamental forms used in metalworking, and it can be cut and bent into a variety of shapes. Thicknesses can vary significantly; ex ...

. It permanently anchors itself to the sheet metal by

swaging Swaging () is a forging process in which the dimensions of an item are altered using dies into which the item is forced. Swaging is usually a cold working process, but also may be hot worked. The term swage may apply to the process (verb) or ...

the surrounding material. Generally, the swage nut is made of a hard metal such as stainless steel, which is inserted into a pre-drilled hole in a softer

ductile Ductility is a mechanical property commonly described as a material's amenability to drawing (e.g. into wire). In materials science, ductility is defined by the degree to which a material can sustain plastic deformation under tensile stres ...

material such as

aluminum Aluminium (aluminum in American and Canadian English) is a chemical element with the symbol Al and atomic number 13. Aluminium has a density lower than those of other common metals, at approximately one third that of steel. It h ...

. The inserted shank has three diameters: a main shaft which fits the hole closely, a thin smaller-diameter undercut, and a larger-diameter serrated clinching ring. Forcing the clinching ring into softer material, with an

arbor press An arbor press is a small hand-operated press. It is typically used to perform smaller jobs, such as staking, riveting, installing, configuring and removing bearings and other press fit work. Punches, inserters, or other tools/dies may be ad ...

or by tightening a screw through the hole, causes it to plastically deform ( swage) into the annular recess in the shank. This locks the nut into the hole. The

knurling Knurling is a manufacturing process, typically conducted on a lathe, whereby a pattern of straight, angled or crossed lines is rolled into the material. Etymology The terms ''knurl'' and ''knurled'' are from an earlier ''knur'' ‘knot in wo ...

on the clinching ring is not necessary for this step, but prevents the nut from rotating after installation. This is a popular method for adding strong, load-bearing threads to a relatively thin piece of soft sheet metal. Self-clinching nuts are described in National Aerospace Standard NASM45938 which supersedes military specification MIL-N-45938

History

Albert Spokes filed for a U.S. patent on the swage nut in early 1958. The swage nut is descended from an older idea, the clinch nut. Clinch nuts incorporate a tubular shaft that fits through the part to be attached and is clinched or riveted in place from the opposite side.

References

{{Nuts (hardware) Nuts (hardware) Fasteners

History

See also

References