Hot extrusion piercing - GIF

[ToolTalkBot]

Hot extrusion piercing.

[sossol]

I made a tool like this out of a broken carbide burr some years ago. I didn't expect my basic drill press have enough power for it to work at all, but it did. Not well, but it did work. My ancient lathe only has 1hp, and I haven't tried with Seig mini mill because it's probablynot torquey enough to do this either.
Neil

[Isambard]

His translation is a bit off. The process is one of friction...

[carl blum]

Hi Gang:
It is interesting, the first hole's thread is cut by a tap, but the second hole uses chipless thread forming.
Carl.