The existence of a drill is no guarantee that you can actually create a hole. I once was a battle tank maintenance guy and we had to replace a cover placed in f

The existence of a drill is no guarantee that you can actually create a hole. I once was a battle tank maintenance guy and we had to replace a cover placed in front of the armor. The replacement had holes in different positions, no problem, just drill a new hole, right? An hour and a few broken drills later we gave up. No doubt there are drills that work on that armor-steel, my point is, depending on the material just any drill may not be good enough. An hour of hard work barely caused a <0.5mm "deep" scratch to appear! PS: We solved the problem by not solving it. Attaching three points instead of four was enough, de decided. That tank would never see a real battle but was only used for training anyway.