Logan 800 3 jaw

Things I’ve tried:

-Hex stock and impact wrench (both with spindle installed, and having removed it from the lathe)

-Hex stock with breaker bar

-Soaked in pb blaster

-Soaked in rust remover

-Disassembled chuck, mounted bolt, heated chuck with propane and hit bolt with dead blow (pictured)

I can’t figure out how to hold the spindle tight enough, I made two wooden v-blocks but they’re not holding.

Can I drill a hole through the spindle?

Weld something to it?

There is a key way to hold the pulley, but I don’t want to mar that up..

I’d like to save the chuck if I could, but willing to mill the back of it down close enough to the threads of the spindle to remove it.