The Secret Life of Components: Springs. 42:13 video:
https://www.youtube.com/watch?v=dethuGX2IGs
Previously:
https://www.homemadetools.net/forum/...689#post178490
https://www.homemadetools.net/forum/...561#post178091
https://www.homemadetools.net/forum/...in-video-84166