Abstract: A nut intended for being retained in a blind hole is provided with a number of lips (11) extending from the cylindrical part (1) of the nut and forming cutting edges (2) which extend most at the upper corner. When these edges (2) are turned in the direction of rotation (10) of the nut when a bolt (5) is being tightened, they will cut further into the wall of the hole. The result is a downturned force which will contribute to securing the nut in the object, and the bolt (5) will not be capable of loosening because the material (6) will be wedged in between the bolt (5) and the lip (11). If the nut is to be withdrawn from the hole, this is most easily done by turning the nut in the opposite direction at the same time while being drawn out. This will cause no appreciable damage to the material in the rim area of the hole.