I've used this a couple of times to repair brake lines on my 2002 Toyota Sienna. It's easy to flare copper nickel lines because they're fairly soft. But, the OEM lines are very hard and covered with a thick plastic. I shaved off a few inches of the plastic and tried to get a good flare. The tool clamps hard, but the tube is pushed away slightly and you can't get a good flare. I marked the tubing just past the tool and could see that it moved. One of the other reviews mentioned using sand paper in the tube slot. I tried 600 grit in the tool on a piece of brake line I had taken off. But, the tube just shifted again. So, I cut a small rectangle of sand paper cloth used for cleaning copper plumbing pipes. I wrapped the brake line with a very small piece of the cloth with the grit on the inside against the brake line. There was just enough sanding cloth to go around the line and not cause too much distortion of the flare tool. On my test piece, it worked and the brake line did not move in the lisle tool. I then used it on the actual line under the van. Again, the line did not shift and I was able to produce a good flare. None of the connections I've made when using this tool have leaked. One of them is over two years old. I've attached a couple of pictures showing the cloth and you can see a tiny piece wrapped around the test piece after flaring. Now, I keep several pieces of the cloth cut into very small pieces in the flare tool case for future projects. This Tool is heavy and solidly built. It is well worth the purchase price if you do your own mechanic work. I'm glad it's the first flare tool I bought. Based on other reviews and my own experience, it's a great tool for a great price.