I didn't read all these replies, but I'm going to reply anyway.
That piloted cobalt drill you have should be fine, can't comment on the other one, but as mentioned, the issue is edge drilling. You simply can't do that with twist drills.
A bi-metal hole saw, or an annular cutter would work, but it's *much* easier to just drill holes in a line, and then cut through them for this particular task.
It's also important to clamp, and back your work. It'll produce better results, less warp and damage to your work piece, and keep you from cutting your fingers off with a spinning helicopter of aluminum. Luckily, it's a tiny drill press. If you tried to do this with either of my mills or my big Powermatic Floor drill by hand, you'd have been in the hospital.
Drills are made for boring semi-round holes in one axis only. Not half moons, not step milling, nothing else.
As James mentioned, you could *easily* do this task with your work clamped vertically in a vise, and using a *quality* round file, get much better results, in probably half the time.