I've used Chapman's for years until a friend's brother died and I bought his entire reloading and tool workshop and got a great Brownell's 58 bit screw driver set that has almost any size and diameter of driver tip. It does make the job easier when you have an exact fit. I wouldn't buy one on my own but this was cheap. The Chapman's is inexpensive and very good.

Grinding the tips of used screwdrivers is a great thing to do. I have fabricated many tools like this when I haven't had the right one at hand. Good way to build up a good gunsmithing tool set.