Rusty I have those small panda vise that pivits on a ball it works ok,as long as you can move around it.
Heres one I made that works better for file work.Its not very difficult to make and as you can see it can be rotated several ways.
The key here is it is narrow at the top and taperd so your file never hits it.
Mine is on a stand in the middle of the room so I can walk clear around it.
It may look big but this liner clamped in it is only 3.5"
Made out of some 3/8" steel I had laying around .drill couple of holes and get couple of bolts to hold it together.