Methods
You don't need much gear to make something similar. I had a propane torch a few fire bricks, a pair of mole grips, a little hammer and a piece of scrap iron with a curve ground into it to act as a swage. When you have done beating the steel about you heat it up to where a magnet just stops sticking to it and then dunk it into water. This leaves the tool steel hard and I just left it that way with no tempering. I am careful not to over stress it. But the reason for risking destruction is that it is such a tiny little poppet that I want it to keep its edge, because it is a bugger to sharpen and there isn't a lot of blade length to assure it a long life. The inside curve is the problem area, actually you need a few sharpening stones as well while you are out shopping for mole grips....
Compressed charcoal on cartridge 29x42cm