David Weaver
Easy to do them much more neatly than those pictures - they're just the result of ripping the end of the pencil off with a chisel to get to the (the groove is always a little wonky at the very end, so I insert the led back from the end a little bit).

Nonetheless, works better and faster than I expected with a good sharp chisel.

I still like putting them in a cordless drill and zipping the ends off with a rotary sharpener, but that will go through sharpeners, and with a fresh pencil, unless you wrap the barrel with something, the chuck marks up the pencil. Easier with a pencil with a metal ferrule. No need to fetch the drill.

I'm guessing the typical chisel bevel is shallower than a knife bevel, thus the preference so far for the chisel.