driving means for rotating the tubular member, electrode and {HEAD ~ conduits} about the elongate axis of the tubular member in first and second directions having a reversible electric motor to provide a driving force and a system of {TAIL ~ gears} for transferring the driving force from the electric motor to the tubular members; and 
driving means for rotating the tubular member , electrode and { HEAD ~ conduits } about the elongate axis of the tubular member in first and second directions having a reversible electric motor to provide a driving force and a system of { TAIL ~ gears } for transferring the driving force from the electric motor to the tubular members ; and
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH