Rebar C-clamp. By Tool Making. 10:42 video:
https://www.youtube.com/watch?v=nYEh8XncbNE
Previously:
https://www.homemadetools.net/forum/...729#post139984
https://www.homemadetools.net/forum/...257#post154089
https://www.homemadetools.net/forum/...352#post161773
