WOODEN GEAR - HARPER FOUNDRY?

This is an enigma. What was its use? The "gear" is made of wood, approximately 7/8" thick and 12" in diameter. It's embossed with metal letters... "HARPER", "13," "78," and "74." Several holes have been drilled through it, and there are a number of random numbers and letters stamped into the wood. It's obviously old, but I could only guess at its age. Unless it was some kind of advertising piece for Harper Foundry either in Jackson or here in Vicksburg, I'm at a loss. Any ideas?

VICKSBURG STATE FAIR & CARNIVAL MEDALLIONS

I can't make out the date on the state fair medal, but it's obviously 18--. Vicksburg enjoyed a rather lofty status during the turn-of-the-century years, for it was the largest town in the state.