Re: How to remove the nut lock?
The die grinder, with a cut off wheel would be the best way to go.
HOWEVER. Use a full face-sheild, and glasses. A dust mask will be a good idea as well.
You most likely do not have a air die grinder. Using a dremel would be like escaping from prison using a spoon to dig the tunnel.
Buy an electric die grinder (straight) and good quality 2"-3" diameter cut off wheels. Norton is the best. And cut that piece of crap in two. Cut where you believe you will catch a little of the bolt. This way, you will be sure the entire piece of crap will release with one cut. If the first threads get roughed up, champher them with the wheel and you will be all set.
Done this before. Works great. Also, If you have a master padlock of any sort that you can't open, you will laugh at how easy the cut off wheel will get through the "case hardend" hasp.
Good luck.
Johnny