Abstract: An insertable threaded sleeve provided with an outer screwthread and an inner screwthread for a screw, the outer screwthread being adapted to the screwthread of a tapped hole in an object. An extension adapted to be deformed by a buckling so as to be locked in the screwthread of the hole is provided with an outer knurling which improves the engagement thereof with the screwthread of the tapped hole and a flange on the outer end. The sleeve is replaceable and can be used in particular when the object is made from a soft material whereas the screw is made from a hard material. It may have if desired means for locking the screw against rotation.