Preferably, the cylindrical aperture comprises {HEAD ~ a cylindrical metal bushing} to receive {TAIL ~ a pivot} pin 
to receive
Preferably , the cylindrical aperture comprises { HEAD ~ a cylindrical metal bushing } to receive { TAIL ~ a pivot } pin
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH