Too Much Coffee

The burrs are made of extremely hard material. For them to lightly touch is unlikely to cause a problem. I do this when I replace the burrs and begin the process of dialing them in. I've looked at burrs under the microscope that accidentally touched while the machine was running and was unable to see any damage. This NOT a recommendation, but it is an indication that the burrs can take some abuse without serious consequences. I've also ground stones (unintentionally) that were in with the beans and the burrs didn't seem to suffer too much. It's probably more important to replace the burrs every couple of years as they seem to wear down from normal use more than from an occasional mishap.

Thanks for the reply, bruceb . Because it was on a new page, I hadn't noticed it until this evening!