In {HEAD ~ fact}, the holes 50 can be formed with {TAIL ~ threads} to receive the inserts 
In { HEAD ~ fact } , the holes 50 can be formed with { TAIL ~ threads } to receive the inserts
OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH