Explain concept of Counter Bore and countersink in radial drilling machine
Counter Bore :-
This operation uses a pilot to guide the cutting action to accommodate the heads =of bolts. Fig. 10 illustrates the counter boring, countersunk and spot facing processes.
Countersink:-
Special angled cone shaped enlargement at the end of the hole to accommodate the screws. Cone angles of 60°, 82°, 90°, 100°, 110°, 120°