I've bought a couple of these and they are good for a few uses then are just no good after that. Guessing diamond files are what i should be looking for. I just hadnt tbought about diamond. Now if i can find some locally would be a bonus too.
Its funny. I live in an area were the population is half a mill, the city is 30+ miles long, and sometimes you cant find what you want locally. Something wrong with this!