On Monday, June 8, 2020 at 1:16:32 PM UTC-4, AS wrote:
...according the the DIN-LN65091, the oval ring has a wire diameter of 8mm, +0, -0.3mm. The round ring has a wire diameter of 7mm, +0, -0.3mm. The O.D. of the round ring is 35mm, +-0.3mm, which would give it a nominal I.D. of 21mm. If you do a quick tolerance stack-up using just min.-max. material conditions while neglecting any ovality, the I.D. could range from 21.9mm to 20.7mm

For those of us who know how to use a pair of calipers, and not much else, what is a quick way to determine that a ring is worn out?