What the heck at 30:53, a miracle occurs and you jump to the surface grinder. Looks like the setup clamp moved from excess vibration, but I'm guessing the material got hot from the lathe work and self heat treated. But that's a guess. Also the end mill is spinning a bit fast, at least for me.
If I understand the video, you removed all the material you were going to mill away on the surface grinder. That had to take an eternity.
Good to see you ended up with a working punch.