The driving mechanism rotates {HEAD ~ the tubular member} and electrode about {TAIL ~ the elongated axis} of the tubular member 
about
The driving mechanism rotates { HEAD ~ the tubular member } and electrode about { TAIL ~ the elongated axis } of the tubular member
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH