In the preferred embodiment of the invention, the flat annular surface 34 at the tip distal end lies in {HEAD ~ a plane} positioned at {TAIL ~ an angle} of 15° to a plane normal or perpendicular to the center axis of the tip 
In the preferred embodiment of the invention , the flat annular surface 34 at the tip distal end lies in { HEAD ~ a plane } positioned at { TAIL ~ an angle } of 15 ° to a plane normal or perpendicular to the center axis of the tip
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH