Must be "Harder Than Hammered Owl $hit, eh? blush

Here's a couple ideas:

Try a flame wrench, clean up the hole with a die grinder.

Or if you have a welder, crank up the amps and burn a hole through it with an electrode, then clean up the hole with a die grinder.

In the Stovebolt Gallery ~~ "The Orange Crate" 1965 C10 SWB Step Side Build Thread

Inspired to be different. Different in a way of my own, not in a way that others strive.