In {HEAD ~ operation}, {TAIL ~ the tube} 20 to be machined is placed in the apparatus 10 
In { HEAD ~ operation } , { TAIL ~ the tube } 20 to be machined is placed in the apparatus 10
OTH HEAD HEAD HEAD HEAD HEAD OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH