If that's the clockwork-type navigation calculator I'm thinking of, it was what I had in mind when I mentioned gears. The catch is, it was not used for power transmission- so efficiency, smooth running, long life at speed were simply not concerns.

Just happened to think- another line of inquiry along this line was A Connecticut Yankee in King Arthur's Court- in which the practical-minded man is transported back in time, and manages recreate enough technology to make a six-shooter.