To the shank, I'd like to replicate the effect of a knurled shank on screwdrivers that don't have a knurled shank.
Having the knurling there when you want to spin it by the shank in your fingertips to get a loosened screw out quickly is great.
Hex, square, and forged finish ( Stanley 100 plus ) shanks do fine, but the smooth chrome round shanks do not unless your hands are clean and dry.
As a teenager I had a set of screwdrivers with knurled shanks which I really appreciated, and I recently began to miss that feature.
I'm not going to just buy a set of screwdrivers for the knurled shanks though because everything else about them still has to be right, and figured I'd come up with a way to sort of add a facsimile of that feature to the screwdrivers I've already got.