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The only way to drill really and truly hard steel is with a carbide drill or a carbide tipped drill. Carbide spade drills are limited to the depth of the hole they can make, a 3/16 drill can only drill about 3/16 deep. I realize that your blade is probably no thicker than 3/16 but that is still operating right at the limit. The best tool for the job is a screw machine length straight flute carbide drill. The cost more but they last longer and work much better leaving glass smooth holes of the nominal size. You can get them at MSC or Enco or McMaster-Carr or most anywhere commercial tooling is sold. You do not need to use lubricant with them and I prefer to use them at low rpms....
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