A hacksaw or a grinder with a cutoff wheel NOT a grinding wheel. If you can get a hold of a portaband use that,makes short work of cutting very thick metal,a cutting torch,a rebar cutter or,what the hell, high explosives!!!!! LOL Just kidding the portaband would be the best,no sparks like the grinder and no slag like the torch. I'm a Sheetmetal worker and have lots of experience with all types of metal,if you wanna do it on the cheap hacksaw.