Coping saw. By Mirock's Toolworks.
6:10 video:
https://www.youtube.com/watch?v=xQg8Gmotw5k
2:28 video:
https://www.youtube.com/watch?v=AyGMC-_h08g
3:18 video:
https://www.youtube.com/watch?v=JVZeKAOmKv0
5:03 video:
https://www.youtube.com/watch?v=cb6T1Utm-s8
3:56 video:
https://www.youtube.com/watch?v=WbNmKfZya1g
2:58 video:
https://www.youtube.com/watch?v=bjN_WklgCEo
3:20 video:
https://www.youtube.com/watch?v=B0ACc1IgZxg
Previously:
https://www.homemadetools.net/forum/...945#post179577