Do NOT use self-tapping screws for fixing into wood. It is a common error whereby many people use self-tapping screws for fixing into wood. Self-Tapping screws are designed for use in metal. For that purpose the threads are closer and of shallow depth. This works well in metals like steel and aluminium.
However, in wood the material density is low and such thread profile would easily lose their grip. Therefore wood screws or chipboard screws need to be used.
Wood screw threads have more depth and a wider pitch. This enables the threads to cut deeper into the base material and hold more of the wood when installed.
Using wood screws for metal is also not recommended as the threads can strip out. There would also be higher stress on the base material and the screw because of the higher thread depth.
A number of innovations have taken place in the design of wood screws and it is worthwhile to consider these when making a selection.
See the EXPANDET wood screws page for more information.