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 ...

So it’s always a joy to pick up a new trick, especially one as simple as putting a hardened edge on mild steel using a drill bit as a filler rod. This tip comes to us by way of [Jody], aka ...

High-speed steel (HSS) is found in most standard ... times until they are too short to use. TCT drill bits, as the name suggests, have a hardened tip. This wears away each time it is sharpened.