The 3rd world videos show how a lack of technology doesn't stop some pretty amazing adaptations to get it done. Old equipment thrown away in other places used to repair and maintain equipment destined for the scrap yard. Lots of labor used in place of mechanization. Sometimes the waste of labor surprises me. Like when they throw parts in the dirt and then pick them up and carry them to the next operation. They could save time & $ by using a cart or better yet relocating the next operation. But they manage to get it done.
This^... This is real.
Look at some of the various mechanized things that get restored (or "restored", depending where you run into it), that were built in the 1800's and early 1900's. They were built with similar precision to this video, and easily managed to produce results that were quite positive when compared to the alternative. For all we know this guy is building donkey cart axles where speed, heat, and general precision is just not all that critical.
But I still think they could have rounded up a wire brush or something. Even a hammer and chisel. That can't be more expensive than the tooling costs of cutting dirt.