really there is no need to cut it off, if you can't get it off it's because you either don't the appropriate puller, or don,t know how to use it. That being said I have cut various pieces off things in my life and this should not be such a big deal. I would start with a grinder and cut a circle halfway bettween the outer circumfrence and the threaded bolt. This would free up the outer part of the drum. Once you had removed that you could go for the tapered section where the drum's center is stuck to the axle shaft. The connection is conical so care must be taken not to damage the 1/2 shaft. You won't need to cut all the way to the 1/2 shaft mating surface with an mil or 2 should do it, then use a chisel to break it free. Good luck with that, but really you should go to a truck mechanic and borrow a decent puller, it will be easier adn in the long run cheaper.