How To Remove A Broken Center Drill

[Paul Alciatore]

On the tip at the end on better center drills, can you explain why the spiral cut one is stronger? The one on the left that you refer to as a straight cut is what I have seen and most, if not all of my center drills are that style. But the one you show looks like it has a very poor finish, possible already cracked. None of mine are like that. They have nice, ground finishes like most of my drill bits and end mills do. Is that the reason why the one on the left is no good? Or what? I would think that they both have about the same amount of cross sectional area at the base of the small diameter area, which is where center drills normally break.

AND, just where do you get those spiral cut ones? What brand? What are they called, other than center drills?