F16B 25/0063

Screws that cut thread in the body into which they are screwed, e.g. wood screws {characterised by geometric details of the screw characterised by the geometry of the thread, the thread being a ridge wrapped around the shaft of the screw the screw having distinct axial zones, e.g. multiple axial thread sections with different pitch or thread cross-sections with a non-threaded portion on the shaft of the screw}