Bingo - you would be surprised just how straight a cut you can make using this method. Another thing that makes it easier is using a smaller 4 1/2" grinder.
I use a few different tools, the Dewalt cut off discs Model: DW8061 listed below work well, a Dremel with reinforced cut off wheel for detailed work, and rarely a Sawzall. You'd be surprised how detailed you can get with a cut off wheel - I like to use the thin Dewalt disc to grind down my...