Here's the jig I use when doing my filing. It is meant to be bolted down, but I just clamp it into a large vise. Notice that the blade clamp head can be rotated completely around, and this helps when doing file work. If I have a deep bevel or plunge cut in mind, I try to forge it in, but on the bowie I did a lot of file and sandpaper work. I hope this pic shows up more detail.