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