When I was stripping down the Cinelli and cleaning parts I noticed that the 42 T chainring had a small hole through the outer circumference below the teeth. This is a patent Campagnolo ring on a no date crank set. The hole drilling is very tidy and looks like what you might see for a chain catcher pin ( but this is a small ring!!! ) and doesn't look home made.
Anyone ever seen this before and what is it for?
Norm Lafleur
Ashfield, Ma.