Bob,
depends on what you need. If it's a LONG feather a couple strips of sheet metal (or a couple steel rules) and some spring clamps would work just fine, mind you roll the edges obviously on the sheet metal.
I've done a few when doing spliced feathers and just used a straight clamp. the feathers were already cut to the length I needed. I also didn't use a belt sander. I used plate glass and sandpaper. I HAD this for sharpening plane blades, glass with a bunch of sandpaper on it. I need to remake the jig after my move 2 years ago, obviously havent done any planing with hand planes lately
. It works well, though to fine of sand paper will take awhile.
I find myself mostly using a straight clamp and a block sander for what little grinding I end up doing anymore.
Also if you're going to do a ton it's dusty, wear a mask!!!
If you ARE going to do a ton, why not build Dean Torge's grinding clamp? It's a helluva lot cheaper then the GN jig (I'm cheap what can I say, though I would like to buy a GN as I'm sure it's better then what I have by a huge margin LOL). The only problem I had was finding a bushing for the bottom of my drum using the Torges clamp. I have a bunch of turkey feathers from this spring I need to grind....one of the many winter projects!