Basically that's 1/2 home through 1/4 thick steel. Hundred holes is a lot of holes. That lil' thing will do it, but slowly. I think you might have to start with a small 1/4 holes and drill twice to get to 1/2" on that. Are they all the same location? Make a jig with some scrap plywood and a hold down or clamp os some type to speed things up. Holding with your hand it aint gonna cut it after 5-8 holes.
I drill a 1/4" hole with a hand drill. Half way through, I already cuss more then I would normally have in two month and I normal cuss more then a drunken sailor
. If you have the space, a floor model with a larger motor will help a lot.