It turns out that a hot solution of alum (ammonium aluminum sulfate), which is available in the spice rack of your local supermarket, will dissolve the steel ... for larger drill bits, but the ...

These are robust steel drill bits, good for drilling into wood ... These include titanium and even crushed diamond. For drilling into metals such as stainless steel, your best bet is a HSS ...

Armed with a diamond hand file, a bit of muscle power, and lots of patience, you can hand-sharpen the drill bits without any power tools. Since you'll be applying force to a sharp metal object ...