Screwdrivers for those very narrow slots in the end after some use I found that they would eventually twist or break. so a long time ago I started to make my own but found that re purposing screwdrivers I in second hand shops and later car boot sales. The main problem a lot of folks find with re grinding screwdrivers for thin slots it was rather difficult not to draw the metals temper ending up with a soft blade. There is a grinder that is more akin to wood working though I now would not be without one though I am not suggesting that you rush out and purchase one but if you are a practical type of person you would wonder why you never purchased one a lot earlier. I am talking of a standard four inch fast grind er with a fast dry stone located at one end and a wet grind stone at the other, Ideal for sharpening hand plane blades and wood chisels to knives and scissors and everything in between. The water stone stops drawing the temper from the steel no matter how thin you grind it to so ideal for hollow grinding screwdrivers. I found that after rough grinding lathe tools from HSS blanks a quick touch up of the cutting edge on the wet stone I could skip the oil stone honing of the cutting edge, the one in the picture is a standard hobby type not a lot of money I have had one for a lot of years now replacing each stone twice for the wet and four times the fast stone.
The picture is a stock one but they all look the same also the cost of the grinder can vary dramatically depending what name is on the thing.