Welding rotator. By Rustinox.
15:27 video:
https://www.youtube.com/watch?v=8_F_BhVAhkQ
17:10 video:
https://www.youtube.com/watch?v=jnEvaRnCJMQ
26:43 video:
https://www.youtube.com/watch?v=YVatODfWqgw
17:42 video:
https://www.youtube.com/watch?v=L_ui_tDqmDE