dont buy a dremel if this is all you intend to do with it, youll destroy it, and its too much $ to waste when a no-name grinder will do for $80. have a crack at grinding a dead head first, get a feel for it, then take it slow on your 'proper' head. its quite easy, but take your time (i took 3 months )...
tooling bits, no dremel part will do, go to gasweld (or equiv) and ask for open tooth grinding burrs in whatever shaft size you need. abut $30-50 each, but they last.