More brainstorming...

Is it possible to make gears without tooth so that it's one steel wheel driving another. May be sandblasting the surface so that the two won't slip. Obviously this type of gear won't transfer much power, but I thought where extremely accurate motion control is required this would be a workable solution. I'm thinking of instrumentation applications may be, where the phases of the two gears must maintain a fix ratio all the time.

Albert