Self-tapping screws (or thread-forming screws) contain threads which are designed to tap their own holes, which makes them ideal for working with softer materials such as wood and plastic. http://www.orbitalfasteners.co.uk
A hardened screw with a sharp point, so designed that its threads cut their own mating threads when inserted and rotated in an appropriately-sized hole.
Screw used to attach material to metal with predrilled hole. As screw is rotated, it threads into hole and remains secure.
A fastener that taps its own threads in a predrilled hole.
A fastener that forms receiving threads when turned into a previously drilled hole.
A fastener which taps it's own threads in a predrilled hole. It is for attaching panels to purlins and girts and for connecting trim and flashing.
Screw with a pointed tip and sharp threads, which allow it to be started and screwed into an unthreaded hole.