In theory it's a good tool and might work well for thin aluminum or maybe thin air ducts but there's no way to cut 20 gauge. The photos I posted were my brief attempt at using a tool to cut old 26g galvanized metal barn paneling. To be honest, the tool was very easy to use. I used the 2x6 you can see in the photos as a guide and was hoping to trim the floor while I installed the manifold on the barn. The tool was slow but that wasn't a problem as I wanted a good cut. The red handle kept slipping, but otherwise it was no worse than using an electric can opener. When he got halfway through the first piece, he started to have problems (it was about a foot cut). When I got to the 2nd siding it basically bent the metal and emphasized the drill bit. After about 18 inches it stopped cutting altogether and ended up smoking my wireless DeWalt 18v. It's not like I tried to cut through a car roof, which is normally a size 20. After the disaster I've pictured here, I tried it out on a plain piece of new L-shaped trim that was thin enough to cut with scissors. The tool couldn't cut it either. The rusty siding I provided was finally trimmed with a pair of plain tin snips so it's not that thick stuff. I was really hoping it would work, but it didn't. after just a few minutes it was completely useless. I had no choice but to return it. This may be enough for a flat 29g can, but anything thicker or more ribbed is likely to ruin the material or any power tool you use.