We use cobalt high speed steel drills when drilling Titanium for diamond setting which are also good on stainless steel - slow the drill right down, don't drill at gold or silver speeds or you will burn it out in no time and use a drop of oil on the drill - WD40 is ok.

For drilling Titanium on the CNC lathe we use special tungsten carbide drills called 'U' drills which take replaceable cutting edge inserts so there is no need to regrind.