A V-block is basically a v, cut into a block that you can place round or strange shaped objects in to cut or drill. I’ve made a dowel cutter for the bandsaw, and while that will work to drill a hole, it doesn’t allow you to attach it to the jig like this does, by using painters tape. Attaching the dowel to the jig gives you hands free access to finding and making a perfectly centered hole…or several holes in succession.