In the preferred embodiment, {HEAD ~ the oblique angle} formed by these end surfaces is {TAIL ~ 15°} from a plane positioned normal or perpendicular to these axes 
In the preferred embodiment , { HEAD ~ the oblique angle } formed by these end surfaces is { TAIL ~ 15 ° } from a plane positioned normal or perpendicular to these axes
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH