Rivet bushes are used to add a threaded hole to a sheet of material, often in order to add a load bearing thread to soft or weak materials. The threadis the helical structure used on nuts and bolts and other fittings that allows them to fasten to one another.
Rivet bushes may also be used to spread a load over a greater area of shear, tension, or torque. They consist of a main shaft, an undercut which is thinner and of smaller diameter, and a serrated clinching ring, which is the part used to secure the rivet bush to the material.
Rivet bushes are inserted into a sheet of material such as sheet metal, usually via a pre-drilled hole. The clinching ring is forced into the softer material, making it deform into the groove on the main shank. This locks the nut in and then allows you to screw something into the threaded hole.
Rivet bushes differ mainly by their dimensions, depending on the size of screw that will need to go into them.