The top of the inner die 3 is processed to form {HEAD ~ a stop portion} 31 with {TAIL ~ a central through hole} 311  
The top of the inner die 3 is processed to form { HEAD ~ a stop portion } 31 with { TAIL ~ a central through hole } 311
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH