Quote Originally Posted by The Puma Man
Just let me say, this is all bull+++t really. I've been a machinist for some 35 years and if a close tolerance is required you just can't rely on hand grinding, it's just not reliable. For open tolerance (0.3 mm) then yes maybe. Close tolerance work drill grinder every time
Perhaps in the hands of some people a drill cannot be sharpened to cut within about 0.002" of size but it can be done. And when you are talking drilled holes with standard HSS bits anyone who thinks they are reliably getting much better than that even with a new drill is dreaming.

Yes it takes time and a drill grinder is faster but it is possible; I was doing it about 44 years ago.