The Combined Tap enables the user to produce the tapping drill hole and the through thread in one operation without any tool changing. The tool incorporates a twist drill before the thread-tapping part. It is possible with this tool to produce through threads up to a maximum threaded depth of 2 x D. The Combined Tap is suitable for universal use in materials of medium mechanical strenght: non-alloyed and alloyed steel sorts up to 600 N/mm2, malleable cast iron, nodulized graphite cast iron, copper, brass, aluminium, aluminium-magnesium and zinc alloys, red bronze, electron metal, pressure-cast zinc. It is sensible to use this tool on machines possesing an RPM switchover facility for drilling and tapping. The feed rate must be adapted to the particular operation required - drilling or tapping. Tapping chucks with pressure compensation may not be used.