You could buy a woodchuck tapering grinder to taper them but it's pretty expensive. A disc sander does great with a jig though. An inexpensive belt sander with sanding disk costs about the same as a woodchuck and is far more handy to have. A ground taper though, either with the woodchuck or in a jig on a sanding disk, is far better than a pencil sharpener tapering tool can ever do anyway.