Originally Posted by Six jours

Andre, you can also "tune" a cog yourself. Use a round jeweler's file and "break" all the sharp edges around the teeth. The same file -- or a dowel with jeweler's rouge, valve grinding compound, or emery paper -- can then be used to polish between the teeth where the chain runs. Finally, you can use a flat file, or -- carefully -- a Dremel-type tool to smooth the machining marks on the teeth themselves. This is essentially what EAI does with the Superstar cogs.

I have no experience with the Gold Medal cogs, but don't think the idea has much merit. I believe the shape and smoothness has much more to do with the feel of the cog than does any coating -- and I'll bet the coating doesn't last more than a dozen hours of use.