Four jaw chuck - videos

Four jaw chuck. By Part Detail.

17:13 video:
https://www.youtube.com/watch?v=ohk_L8BGA8w

21:00 video:
https://www.youtube.com/watch?v=8lRNIBmHOo8

Application ?

Part 3. By Part Detail. 38:22 video:

https://www.youtube.com/watch?v=kgVI92ti-qM