Reliable Paper has the 10″ Nicholson Magicut files on sale for about $8. It’s not the sexiest thing to slobber over, but it will save your rear one day when you need to remove a few burrs and don’t want to fire power tools back up, or if the material is Italian — you know, fragile.
Magicut files have chip breaker grooves which make them ideal for plastics and aluminum that will clog a regular file. They give a smooth shearing cut while removing material quickly. It’s one of my favorite files in my own shop.
10″ Nicholson Magicut File [Reliablepaper.com]