Sheet metal screws, also commonly known as tapping screws, are used to join thin gage sheet metal. Generally harder than machine screws, sheet metal screws require a preformed hole to be effectively employed. The most common sheet metal screws are a Type A with coarse spaced threads and a sharp gimlet point, the Type AB which has more narrow thread spacing and a gimlet point, and the Type B which has a blunt point and threads spaced like an AB.