Yep, us farmers don't wear rings while running machinery.
I am sure it is because we are afraid to mar the green paint on that old 4020.
My son wears a Tungston wedding band. I suppose it might scratch some metals. But I am more concerned of the damage it might do to the digit if it gets hung up.
He is in an H-VAC apprenticeship program, I guess that beats baling hay or running a lathe as far as risk assesment goes.
Me, I have never had a ring of any kind on my hands. My wife thought I needed a band when we got married. I told her not to waste her money, as I would refuse to wear it.
She had her feelers hurt for a few months, even after I told her a few horror stories of ring induced injuries.
It has been almost 34 years, and I have never forgotten for a moment that I was married to a wonderful woman. Have never needed any ring to remind me.