When I shot wood, I made a jig from 3/4 plywood to clamp on my disc sander table. Just took a foot by foot pc,and laid out the tapers wanted with a protractor.
Then took a router with a v-groove bit , clamped a strait pc to the jig on the line and routed a groove on the jig for both angles coming out just beside each other.
Quickclamp the jig to the sander table and hold the arrow shaft down with one hand and turn with the other.
I tried screwing a pc on top of the jig first,but was hard to keep the shaft against it good,so went to the v-groove.
Mine worked like a champ,lots easier than using one of the pencilsharpener types.