I have used this knife to cut 0.050mm thick aluminum it cuts like butter. Using a ruler against the muzzle works well for cutting smooth, straight lines. It takes a steady hand to cut a smooth and precise curve, but it's not difficult to achieve. I should mention that die cutting machines are not circular saws where you can see the cutting process and control accordingly. With the die cut you'll see a 1/4 inch cut after he makes the cut and it's really maneuverable so if you're not careful you'll end up wiggling back and forth all over the place. That's my only reason for rating this tool 4 stars instead of 5. The muzzle ruler completely solves this problem. I've read complaints from some people who think the moon shaped cutouts are sharp and distracting but I just vacuumed them up and they really aren't IR 325B very well done and powerful replacement bits are available from IR meaning this tool lasts for years.