Grinding a twisted shaft - GIF

[Altair]

Grinding a twisted shaft.




Previously:

Forming a twisted tape turbolator - GIF
Twisted hex chess set - photos and videos
Homemade metal twisting machine - video
Red hot picket twisting - GIF
Twisted PTO shaft - GIF

[IntheGroove]

That's a rotor for a progressive cavity pump. Long ago I worked for my uncle that had a drywall spraying equipment manufacturing company. We used to make those with hydraulic tracer lathes...

[desbromilow]

Mono pumps use something similar with a flexible chamber to pump water/ slurry with suspended solids. - last saw one in the mid 1990s at an ag show for pumping dirty water.