[davidmanze]

Huh... I tried adapting one to my camera but stopped quickly as it was leaking oil.
My country has a lot of positive features but the quality of optics coming out of it (especially the old ones, though I have no idea of the modern products, if any) is definitely not one of them.
That notion notwithstanding, I'd be curious to find and adapt that Industar lens I saw kicking around my parents' home in the days of yore... just for giggles.

....... Russian optics were known for using T34 tank grease, thick and black  ... which separates with the course of time into oil usually on the aperture blades ..... 
 ...... a grease change is recommended every three thousand miles .......

ah ..... that "Industar" !! (Leica M39mm mount) ..... one of the most unusable lenses on the planet ...... to have the aperture ring mounted "on the focusing ring" which is three times as stiff as the focusing ring itself ...... is just pure genius !!
  
  The Helios M44-2 solved that with it's very light to turn "preset ring" ........ the ultimate in deluxe features at the time ......

 ...... actually preset rings could still work today where there are no aperture automations with Chinese manual dumb lenses ....... a preset ring is much faster to turn with one finger than a click stop aperture ring.