Ring roll forging.
<video controls autoplay loop> <source src="https://s3-us-west-1.amazonaws.com/hmt-forum/hot_fiery_rollers.mp4" type="video/mp4"> Your browser does not support the video tag. </video>
Previously:
https://www.homemadetools.net/forum/...647#post174419
https://www.homemadetools.net/forum/...027#post164586
https://www.homemadetools.net/forum/...988#post133915
https://www.homemadetools.net/forum/...774#post159797
https://www.homemadetools.net/forum/...2847#post97293