bench grinder or drill press....I also use the GN feather jig but on a drill press works well.
mine however is cocked funny (older drill press). So I had to add a few shims to straighten the quills out, not a big deal in the grand scheme...they come out great!
I also built a Dean torges jig, and it works well as well *and is much cheaper LOL*, but you'll still need the drum with a spacing disc on the bottom, or learn to free hand.
I have a pile of feathers to get done this winter!!!!