In one approach a solid metal disk has {HEAD ~ blades} machined from {TAIL ~ its periphery} 
machined from
In one approach a solid metal disk has { HEAD ~ blades } machined from { TAIL ~ its periphery }
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL