Forgefix coach screw hexagon head single thread zp in bags forgefix 5cs16100 these forgefix single thread coach screws are zinc plated for increased corrosion resistance their hex head enables higher torque capability when tightening and increased speed of use with socket drivers these coach screws conform to din571 standards used widely in heavier timber installations and for fixing timber to masonry also popular as a fixing for satellite dish installation together with a rimmed or riml