That disc is really meant for grinding surfaces of metals and not meant for cutting like you just did. I have two of them and great when both need to on metal.
The one that came with the grinder I know it's meant to grind surfaces. I had purchase like 2 25 packs of cut off disks specifically to cut through flat metal like this. At any rate I'm at hhe midst of trying different blade designs. And use a combo old school files for certain things om the blade. And use my rotary tool station for other kind of grinding on it. And maybe an oscillating tool with some really good paper to get that mirror look.
Why would you use the grinding tool to cut - that disc you have is to grind surfaces - the cutting disc ( not included ) would cut through that like butter
