That big hole in the center can be easily done, even with an electric hand drill.

Here's how:

http://www.amazon.com/Neiko-Titanium...6880667&sr=1-1



I needed to drill some huge holes in copper when I made a boiler. I had never used the step drills before, so I gave it a try. Man, it was super easy, and cut clean and precise.

Are you looking for 25's or 40's? I got some 40's.