Dowel screw for use with e.g. window grill, has hexagon socket and internal thread provided in screw head, where passage from head to shank is provided with radius and screw is screwed into dowel till upper edge is aligned with plaster

摘要

The screw has a hexagon socket (9) and an internal thread (10) that are provided in a screw head, where a passage from the head to a shank is provided with a radius (5). The screw is so deeply screwed into a dowel (1), by a 6- edged key, till an upper edge (3) of the screw is aligned with an external plaster, after boring and inserting the dowel into a supporting frame (2).