I use a file grinder mainly for grinding welds on a VW T2 bus. So far I have removed the front floor, dog feet, inner and outer rocker panels and wheel arch liners. I doubt I could have done the job without this grinder (the bus is so rusted I can't see where the spot welds are so drilling isn't an option). With Cubitron belts (60+ grit) they can remove maybe a meter of 18 gauge steel before they wear out (they hold up surprisingly well with this grinder). I would highly recommend a grinder for this type of work.