Abstract: A dowel for a lightweight building material contains on its outside a self-tapping thread and at its tip a cutting edge with which it can be screwed into a plasterboard. At the end opposite to the tip the inner opening of the sleeve is constructed with a hexagonal cross-section, to which is connected an area of the inner opening in which the screw can cut its own thread. The area of the bit intended for engagement in the chuck of a driving tool is used for screwing in the dowel, because this hexagonal area projects somewhat from the chuck, so that it can engage in the hexagonal recess of the dowel sleeve.