In order to machine {HEAD ~ a hexagonal profile} of {TAIL ~ extended axial length} it is of course necessary to advance the tool 17 progressively as the machining operation proceeds, and this is accomplished by the drive mechanism comprising the lead screw 116 
of
In order to machine { HEAD ~ a hexagonal profile } of { TAIL ~ extended axial length } it is of course necessary to advance the tool 17 progressively as the machining operation proceeds , and this is accomplished by the drive mechanism comprising the lead screw 116
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL 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 OTH OTH OTH