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