In {HEAD ~ one threading tool}, {TAIL ~ the insert cross section} forms substantially a hexagon with two opposite sides longer than the other four sides  
In { HEAD ~ one threading tool } , { TAIL ~ the insert cross section } forms substantially a hexagon with two opposite sides longer than the other four sides
OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH