Wow, "bolts", "tapered", "drill bit", "82 degree angle", "flush mount", "center drill", "lathe", "aluminum" (and all spelled correctly). Who do you think you're kidding, you've got some experience alright
An 82 degree countersink is what you would be looking for. The so called 'zero flute' style is highly recommended. That is the kind with the hole drilled through the body of the tool to form the cutting edge.
First you get good, then you get fast. Then grouchiness sets in.
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)