The apparatus of the present invention also includes {HEAD ~ means} for driving {TAIL ~ the cutting tool assembly} into and out of engagement with the tube 
for driving
The apparatus of the present invention also includes { HEAD ~ means } for driving { TAIL ~ the cutting tool assembly } into and out of engagement with the tube
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH