Minh,
I feel your pain on the crankshaft. I "learned" 2 times on HOW NOT TO DO IT! Then on the third try, using advice from this forum, I succeeded. When doing cranks from a solid round, make biscuits to snugly fit between the webs. Then when you push the live tailstock center in to hold it, the biscuits take up the pressure and you shouldn't have problems.
Grasshopper
I feel your pain on the crankshaft. I "learned" 2 times on HOW NOT TO DO IT! Then on the third try, using advice from this forum, I succeeded. When doing cranks from a solid round, make biscuits to snugly fit between the webs. Then when you push the live tailstock center in to hold it, the biscuits take up the pressure and you shouldn't have problems.
Grasshopper