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 drill bit without reacting with the brass.

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 ...

There are three tool options to consider when drilling large-diameter holes in thick steel: twist drill bits, hole saws and ... bore annular cutters can be used with hand-held drills, but they ...

Cut holes in steel quickly ... regular drill bits. Ideal for clean and burr-free cutting. 3/4" Weldon shank with 2 flats - fits most major brands of magnetic drills, can also be used with machine ...

whereas cobalt is typically used for harder materials like cast iron or stainless steel. Tungsten-carbide tipped (TCT) and titanium nitride coated (TiN) drill bits are also popular. HSS is hard ...