The axle works fine but you have to make sure before every hammer hit it gets screwed back tight to positively lodge against the crank material. A whack or two lets the softer axle end impress enough to back away from hammer action metal reshaping to let a space enter and then the hammer whacks only stress the rotor threads with nothing going into the crank end itself. Axle having even .005" clearance and the impact won't touch it. MUST be solid against the crank to produce enough interference stress to pop it loose.
Never seen one that was constantly adjusted up after every whack take more than 3 whacks to pop it off. If rusted like engine lower end it may be stuck on to stay. More force needed but don't be surprised if crank damage ensues. Do NOT use a small hammer like for construction, bigger one to take inertia effect better, is best there, I never use a small one. And solid metal, no plastic hammer. I use baby sledge and then I hold back on the force, let the weight do the work.
Screw some bolts back in to positively hold case halves together, you will damage all mains not doing so, the looseness lets the crank deflect in the holes with loose cases. Now you are battering your mains.
Luck.