Since {HEAD ~ the smaller diameter parallel thread part} 15 has {TAIL ~ so small diameter}, the steel plate is seldom deformed 
has
Since { HEAD ~ the smaller diameter parallel thread part } 15 has { TAIL ~ so small diameter } , the steel plate is seldom deformed
OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH