Have you ever in your life tried to use an angle grinder for this sort of thing? It’s one of a family of cutting tools built on the Ouija board principle. It transforms human energy into a crooked, unpredictable motion, and the more you attempt to influence its course, the more dismal your future becomes.

If i had a cast iron pan I had to flatten, I’d dog it down on my CNC router, set up a 1/4” endmill, whip up some code for 33% overlapping passes in Fusion 360, and take off .005” layers until it was flat.

Most of us don't have CNC routers sitting around doing nothing.

While angle grinders are useful and all, wouldn't the right commonly available tool for this be something like an orbital sander?

Something like this: https://www.bunnings.com.au/bosch-blue-250w-random-orbital-s...

Or for a US version: https://www.milwaukeetool.com.au/power-tools/carpentry/sande...

Since it wasn't obvious - the inside of the pan :D

Using what kind of attachment?

Flap disc… https://www.amazon.com/Flap-Grinding-Disc-Assorted-Pack/dp/B...

a flap disc.

Seems like overkill though. You could probably just hand sand it to be honest.

I used a flexible grinding disk.

Tools exist to make jobs easy. There is no virtue in doing hard work for hard works sake. Plus, orbital sanders tend to inflame my carpal tunnel.

Probably, random orbital sander would do the trick, but slower and chew through a lot of sanding discs. It took me years to finally acquire a grinder - just no real need between sanders and saws. Once I started working on concrete and metal it became necessary, and now it seems like a luxury for all the little things which I probably should have been enjoying a long time ago. But IME, most people under 40 don’t have an angle grinder laying about. So borrow one from a 40+ friend before making the ROS do the work, IMO.

I didn't even wear out one disk using my 5" ROS sanding a 12" lodge skillet, though I started at 80 grit and worked my way to 220.

GTK, that’s better than I would have expected.