Does the cut have to be clean? If you know someone with a portable plasma cutter, that would be the best choice. Leaves a burn mark on the cut so you would have to undercut and finish off with a grinder. If you are a patient man, you could do it with a variable speed jigsaw. I've found bosch or porter cable to be the best. Be prepared with handful of blades (metal cutting, fine tooth). Once it burns, change it. Need to cut 1/4" at a time, letting blade cool after each cut. Cutting oil helps too. SS is a pita to work with.