First piece of advise, WEAR SAFETY GLASSES!
For the situation you describe, I would recommend a hole saw. Use lots of cutting oil and back out to relieve chips often with compressed air. If you don't relieve the chips, the saw will bind up in the hole and break. A hand drill or drill press should be OK for a hole saw for up to 1". Don't go over 250 to 350 RPM. The bigger the hole, the slower the RPM. You're going to be awhile getting through 1/2" of metal.
A better alternative would be a heavy duty magnetic base drill setup.
With regular drill bits, don't go over 1/2" with a hand drill, the torque will rip the drill right out of your grip. Harbor freight drill presses don't cut the mustard either. For bigger holes, I drill in increments till I reach the size I need. For that, a Bridgeport mill with the work well clamped is a minimum setup.
I give this advise after a lifetime working as a machinist in the metal working trades. Work safe & good luck.