The 400 my dad picked up for me has a 2 1/4" thread adapter for the 4 jaw chuck that is stuck on the spindle. Ive tried a couple of strap wrenches but so far I haven't been able to remove it. I'm reluctant to heat it but suppose I might put some compressed air through the spindle to protect the bearings but if I do get it hot enough to move I wont be able to use my strap wrench. The lathe came with a 3 jaw chuck and a face plate with 1 1/2"-8 thread but of course I cant use them with the adapter in place. I have a blank 1 1/2-8 threaded back plate ordered to remount the 4 jaw with the intention of turning the adapter off. Expecting (hoping) I will hit the bottom of the adapter before hitting the major diameter of the spindle thread and then be able to peel off the threads. I've no experience cutting threads yet but I do have the tools and change gears if it becomes necessary. Anything else I should be considering?