Bit In Red Tube Viking Drill
Premium 135° split point drills will substantially outperform cobalt drills in work harding stainless steel applications. Performance when new is as twist drills, but performance does not fall off as much over time, due to the hard coating. Flat bits tend to produce entry surface splintering, make a hole with rough sides, and make a mess of the exit side.
Viking Drill and Tool
Some of these problems can be avoided by placing scrap wood under the workpiece. Drilling progress is slower than with other types, so flat bits are not best suited to drilling large numbers of holes, nor to cordless use. Apply enough pressure to cut, but not too much.