Sheetmetal bender. By Rock & Fix. 19:53 video:
https://www.youtube.com/watch?v=uL8d8ayns4Y
Previously:
https://www.homemadetools.net/forum/...483#post173759
https://www.homemadetools.net/forum/...795#post183187
https://www.homemadetools.net/forum/...926#post175652