Ok, this is an arbor for some type of disc. Perhaps a saw blade, a cutoff wheel, a flat sanding wheel? Good for close quarters work.
You are on the right track..... keep going...... think how this might work.....ejant said:Wild guess, a nail driver.
You chuck this in a drill. The finishing nail goes in where some ball bearings hold it while you drill the nail in through the molding then you hammer it the rest of the way.........ejant said:It spins the nail. Hepls prevent spliting in the wood. The "o" ring in the grooce keeps a pin in place from falling out. The pin will hold the nail in place.