I tried the die grinder with van's cut wheel but since I am so impatient and didn't want to cut this all day I went to harbour freight and got an angle grinder for $10 and another $10 for a package of thin metal cutting disc's. It done the job faster and just as well and so far no cracked canopy. After filing(which also is a no-no), sanding and using the trim tool John let me use, I made it thru