Small hammer from crescent wrench handle. By not2fast4u2c. 2:56 video:
https://www.youtube.com/watch?v=kax0l5COOkE
Previously:
https://www.homemadetools.net/forum/...812#post171159
https://www.homemadetools.net/forum/...987#post168121
https://www.homemadetools.net/forum/...755#post159731
https://www.homemadetools.net/forum/...256#post154088