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