As the title states, I've got a set of cranks mounted on a bottom bracket without a spindle running through the middle. I got this bike as a gift, and some idiot before me decided the best way to try and steal the cranks was to bang out the spindle. Since I have nothing to press against with the crank arm remover tool, I'm at a loss as to how I'm going to get these off without pulling out the angle grinder.

I've already tried chiseling with a screwdriver (now broken), a thicker screw driver, and an actual chisel. I've also tried just banging on the back of the crank arms. Any help would be appreciated - I need to get these cranks off this columbus frame .