The angle between the bottom surface 35 of the insert 21 and the sidewalls 59 of the insert is typically equal to or greater than the angle between the bottom surface 55 of {HEAD ~ the recess} 53 and the sidewalls 57 of {TAIL ~ the recess} 
The angle between the bottom surface 35 of the insert 21 and the sidewalls 59 of the insert is typically equal to or greater than the angle between the bottom surface 55 of { HEAD ~ the recess } 53 and the sidewalls 57 of { TAIL ~ the recess }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH 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 OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL