Crank polishing
This large belt fixture standing up on this lathe is for polishing cranks. Your arms would fall off using that leather shoe string method after a couple journals.
They not only must be smoothe they must be concentric, flat, and round, And every journal must be the exactly same
My grand pop did a old briggs single when I was younger with the string and crocus cloth method. I got tired just watching and went in the house. I remember my Grams rubbing some stinky ointment on his arms afterwards.