I drilled a new hole in my 15g SS Megapot today and thought I would share the experience.
The goal was a 1/2" hole for my thermometer. I used a water hose to keep it cool and prevent work hardening. A towel was placed under it and rolled up under the sides to prevent it from scratching and rolling around on the ground. I used a 16 penny nail to create a divot, then drilled a small pilot hole with a very small drill bit. I then drilled two more holes consecutively bigger, then the final 1/2" bit.
In hindsight it would have been worth doing it with a Unibit instead. The burrs from the regular bits were pretty bad and I had to use a file to remove them. A Unibit would have removed them nicely.
Overall I was happy with the result though.