>>1860283>I've tried hammering, it only flattened it against the cotterYou mean you hammered the threaded end? And the threaded part "flattened"/mushroomed out?
Anyway, check these pics. It's... similar to what you should have done.
First nut is the one that's usually on the cotter. The second nut is one with the threads drilled out. Really, you can use anything that fits over the blunt end of the cotter (socket, etc). And then you fucking crank on your clamp to get the thing out. Here it's a vise, which is impractical, but a good reminder of how much force is involved. A beefy C-clamp works well, and it's no surprise that a cotter pin press looks like one.
