We've had our discussions about shredders v. slicers v. plug cutters. And then there were the "tobacco grinders" that turned out to be sausage stuffers.
That wooden ring gauge might have been from a turn of the 20th century factory (a la Samuel Gompers) that still hand-made all their cigars, and simply sorted them by ring, after the fact. Or it could have been used for QA. But it clearly pre-dates the truly fat ring size cigars of the last 25 years.
The objects are often boring, while their history can be fascinating.
Bob