What I have found that works for me is a cobalt drill bit in a drill press turning as slow as the drill press will go. The secret to drilling steel is high pressure slow speed sharp bit and keep it cool. If the rivet breaks free and starts to turn in the hole then you should be able to brass punch it out. Use the exact diameter or 2k under punch of the shaft of the rivet make sure you support the workpiece from all points to prevent bending. I have dremeled out cutting boards to custom fit my work. Just my opinion hope it helps.