This is what I do. Even some 1/4" broken bolts, I'll tig a nut to it through the center of the nut and then apply an impact gun to back it out, or if drilling is required, use a right hand drill to make a hole and use the left hand spiral bolt extractor to get the bolt out.
Unfortunately a lot of folks don't drill the hole squarely and get into the host threads then try to remove the broken bolt which then becomes impossible.
