Dave's answer was very good... but he probably has not run into a power steering pulley which needed to come off on a car which had been turned using that nut..... TCane had that situation from the PO of the car... and it was a real bear... it took several heatings with an oxy-acet torch and then still a big hammer.... not fun.... it is a tapered shaft that pulley is on....
The Factory shop manual specifies that the crank bolt should be used to rotate the engine...