I recently acquired a used bike that had a U-Lock attached to the frame. I started with a hacksaw, which would have taken an hour. I decided to try my Dremel with some metal cutting wheels. Two wheels and about 25 minutes later it was off (with a little help from the hacksaw). It was a pain getting that thing cut. I'm sure if I had a larger angle grinder if may have been quicker, but I have to say my hat was off to the manufacturer on how solid it was forged.