I used to build airplanes a long, long time ago. We used these stainless steel brushes, called bonding brushes, for removing paint around a hole before we made an electrical connection to that surface. They had pilots and a few different ways to connect to your drill motor. If you were too aggressive, you could easily spotface into the metal surface. Now that some of you know what I'm talking about, could any of you give some thought to how well these would work for smoothing the inner and outer edges of a trimmed case? I could go get a new brush from Amazon, but that's a $40 experiment. If someone happens to have one with a close sized pilot just floating around your garage and could test the theory, it would be greatly appreciated.