I am replacing the shaft in a large squirl cage fan its 4' dia. has a 60" 2 7/16" solid shaft. I need advise as to how to get the wheel off. I understand how to heat and quench it, my question is how do i get the heat out of the shaft fast enough to make it work. The mass of the shaft is more than that of the hub on the wheel, or do i need a large enough BTU torch to get the hub hot faster? i cant damage the wheel. Is there any other option for getting this done.