after roughing a 6'' hole in .063 alum. sheet i found a very easy, smooth, way to finish the edge out to the trim line. i chucked a straight edged router bit from my woodworking shop into a die grinder.totally smooth and predictable. the edge is smoother than a file and 20 times quicker.
i removed 1/8'' material around the entire hole in 15-20 minutes.
i removed 1/8'' material around the entire hole in 15-20 minutes.