These openings can be {TAIL ~ holes} or {HEAD ~ small bores} extending from the top surface through the bottom surface of the base member 
These openings can be { TAIL ~ holes } or { HEAD ~ small bores } extending from the top surface through the bottom surface of the base member
OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH